Elbow assembly

ABSTRACT

Elbow assembly including a swivel component (6610) connected to a patient interface (6000) by a pair of spring arms (6650) and coupled to an elbow component (6620) by ball and socket joint and a hinge joint (6645) which allows pivoting about a single axis. Hinge joint prevents the elbow component from contacting the spring arms. Swivel component includes inner radial wall (6630) and outer radial wall (6632) defining radial channel (7633) leading to vent holes (6640) for gas washout, tracks or guide walls (7637) within the channel providing discrete flow paths to the vent holes, an inwardly extending lip or chevron (8631) redirects flow to reduce noise and/or minimize flow directly onto sensitive parts the face. Ball portion (6662) includes opposed recesses (6664) engaged with pivot pins (6645) on swivel component to form the hinge. Elbow component houses a pair of anti-asphyxia valves (6680).

1 CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/222,435, filed Sep. 23, 2015, and U.S. Provisional Application No.62/376,718, filed Aug. 18, 2016, each of which is incorporated herein byreference in its entirety.

2 BACKGROUND OF THE TECHNOLOGY 2.1 Field of the Technology

The present technology relates to one or more of the detection,diagnosis, treatment, prevention and amelioration of respiratory-relateddisorders. The present technology also relates to medical devices orapparatus, and their use.

2.2 Description of the Related Art 2.2.1 Human Respiratory System andits Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe air into the venous blood and carbon dioxide to move out. Thetrachea divides into right and left main bronchi, which further divideeventually into terminal bronchioles. The bronchi make up the conductingairways, and do not take part in gas exchange. Further divisions of theairways lead to the respiratory bronchioles, and eventually to thealveoli. The alveolated region of the lung is where the gas exchangetakes place, and is referred to as the respiratory zone. See“Respiratory Physiology”, by John B. West, Lippincott Williams &Wilkins, 9th edition published 2011.

A range of respiratory disorders exist. Certain disorders may becharacterised by particular events, e.g. apneas, hypopneas, andhyperpneas.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterized by events including occlusion or obstruction ofthe upper air passage during sleep. It results from a combination of anabnormally small upper airway and the normal loss of muscle tone in theregion of the tongue, soft palate and posterior oropharyngeal wallduring sleep. The condition causes the affected patient to stopbreathing for periods typically of 30 to 120 seconds in duration,sometimes 200 to 300 times per night. It often causes excessive daytimesomnolence, and it may cause cardiovascular disease and brain damage.The syndrome is a common disorder, particularly in middle agedoverweight males, although a person affected may have no awareness ofthe problem. See U.S. Pat. No. 4,944,310 (Sullivan).

Cheyne-Stokes Respiration (CSR) is another form of sleep disorderedbreathing. CSR is a disorder of a patient's respiratory controller inwhich there are rhythmic alternating periods of waxing and waningventilation known as CSR cycles. CSR is characterised by repetitivede-oxygenation and re-oxygenation of the arterial blood. It is possiblethat CSR is harmful because of the repetitive hypoxia. In some patientsCSR is associated with repetitive arousal from sleep, which causessevere sleep disruption, increased sympathetic activity, and increasedafterload. See U.S. Pat. No. 6,532,959 (Berthon-Jones).

Respiratory failure is an umbrella term for respiratory disorders inwhich the lungs are unable to inspire sufficient oxygen or exhalesufficient CO₂ to meet the patient's needs. Respiratory failure mayencompass some or all of the following disorders.

A patient with respiratory insufficiency (a form of respiratory failure)may experience abnormal shortness of breath on exercise.

Obesity Hyperventilation Syndrome (OHS) is defined as the combination ofsevere obesity and awake chronic hypercapnia, in the absence of otherknown causes for hypoventilation. Symptoms include dyspnea, morningheadache and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a groupof lower airway diseases that have certain characteristics in common.These include increased resistance to air movement, extended expiratoryphase of respiration, and loss of the normal elasticity of the lung.Examples of COPD are emphysema and chronic bronchitis. COPD is caused bychronic tobacco smoking (primary risk factor), occupational exposures,air pollution and genetic factors. Symptoms include: dyspnea onexertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses manydiseases and ailments that impair the functioning of the muscles eitherdirectly via intrinsic muscle pathology, or indirectly via nervepathology. Some NMD patients are characterised by progressive muscularimpairment leading to loss of ambulation, being wheelchair-bound,swallowing difficulties, respiratory muscle weakness and, eventually,death from respiratory failure. Neuromuscular disorders can be dividedinto rapidly progressive and slowly progressive: (i) Rapidly progressivedisorders: Characterised by muscle impairment that worsens over monthsand results in death within a few years (e.g. Amyotrophic lateralsclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers);(ii) Variable or slowly progressive disorders: Characterised by muscleimpairment that worsens over years and only mildly reduces lifeexpectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic musculardystrophy). Symptoms of respiratory failure in NMD include: increasinggeneralised weakness, dysphagia, dyspnea on exertion and at rest,fatigue, sleepiness, morning headache, and difficulties withconcentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result ininefficient coupling between the respiratory muscles and the thoraciccage. The disorders are usually characterised by a restrictive defectand share the potential of long term hypercapnic respiratory failure.Scoliosis and/or kyphoscoliosis may cause severe respiratory failure.Symptoms of respiratory failure include: dyspnea on exertion, peripheraloedema, orthopnea, repeated chest infections, morning headaches,fatigue, poor sleep quality and loss of appetite.

A range of therapies have been used to treat or ameliorate suchconditions. Furthermore, otherwise healthy individuals may takeadvantage of such therapies to prevent respiratory disorders fromarising. However, these have a number of shortcomings.

2.2.2 Therapy

Continuous Positive Airway Pressure (CPAP) therapy has been used totreat Obstructive Sleep Apnea (OSA). The mechanism of action is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion, such as by pushing the soft palate andtongue forward and away from the posterior oropharyngeal wall. Treatmentof OSA by CPAP therapy may be voluntary, and hence patients may electnot to comply with therapy if they find devices used to provide suchtherapy one or more of: uncomfortable, difficult to use, expensive andaesthetically unappealing.

Non-invasive ventilation (NIV) provides ventilatory support to a patientthrough the upper airways to assist the patient breathing and/ormaintain adequate oxygen levels in the body by doing some or all of thework of breathing. The ventilatory support is provided via anon-invasive patient interface. NIV has been used to treat CSR andrespiratory failure, in forms such as OHS, COPD, NMD and Chest Walldisorders. In some forms, the comfort and effectiveness of thesetherapies may be improved.

Invasive ventilation (IV) provides ventilatory support to patients thatare no longer able to effectively breathe themselves and may be providedusing a tracheostomy tube. In some forms, the comfort and effectivenessof these therapies may be improved.

2.2.3 Treatment Systems

These therapies may be provided by a treatment system or device. Suchsystems and devices may also be used to diagnose a condition withouttreating it.

A treatment system may comprise a Respiratory Pressure Therapy Device(RPT device), an air circuit, a humidifier, a patient interface, anddata management.

Another form of treatment system is a mandibular repositioning device.

2.2.3.1 Patient Interface

A patient interface may be used to interface respiratory equipment toits wearer, for example by providing a flow of air to an entrance to theairways. The flow of air may be provided via a mask to the nose and/ormouth, a tube to the mouth or a tracheostomy tube to the trachea of apatient. Depending upon the therapy to be applied, the patient interfacemay form a seal, e.g., with a region of the patient's face, tofacilitate the delivery of gas at a pressure at sufficient variance withambient pressure to effect therapy, e.g., at a positive pressure ofabout 10 cmH₂O relative to ambient pressure. For other forms of therapy,such as the delivery of oxygen, the patient interface may not include aseal sufficient to facilitate delivery to the airways of a supply of gasat a positive pressure of about 10 cmH₂O.

Certain other mask systems may be functionally unsuitable for thepresent field. For example, purely ornamental masks may be unable tomaintain a suitable pressure. Mask systems used for underwater swimmingor diving may be configured to guard against ingress of water from anexternal higher pressure, but not to maintain air internally at a higherpressure than ambient.

Certain masks may be clinically unfavourable for the present technologye.g. if they block airflow via the nose and only allow it via the mouth.

Certain masks may be uncomfortable or impractical for the presenttechnology if they require a patient to insert a portion of a maskstructure in their mouth to create and maintain a seal via their lips.

Certain masks may be impractical for use while sleeping, e.g. forsleeping while lying on one's side in bed with a head on a pillow.

The design of a patient interface presents a number of challenges. Theface has a complex three-dimensional shape. The size and shape of nosesand heads varies considerably between individuals. Since the headincludes bone, cartilage and soft tissue, different regions of the facerespond differently to mechanical forces. The jaw or mandible may moverelative to other bones of the skull. The whole head may move during thecourse of a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being oneor more of obtrusive, aesthetically undesirable, costly, poorly fitting,difficult to use, and uncomfortable especially when worn for longperiods of time or when a patient is unfamiliar with a system. Wronglysized masks can give rise to reduced compliance, reduced comfort andpoorer patient outcomes. Masks designed solely for aviators, masksdesigned as part of personal protection equipment (e.g. filter masks),SCUBA masks, or for the administration of anaesthetics may be tolerablefor their original application, but nevertheless such masks may beundesirably uncomfortable to be worn for extended periods of time, e.g.,several hours. This discomfort may lead to a reduction in patientcompliance with therapy. This is even more so if the mask is to be wornduring sleep.

CPAP therapy is highly effective to treat certain respiratory disorders,provided patients comply with therapy. If a mask is uncomfortable, ordifficult to use a patient may not comply with therapy. Since it isoften recommended that a patient regularly wash their mask, if a mask isdifficult to clean (e.g., difficult to assemble or disassemble),patients may not clean their mask and this may impact on patientcompliance.

While a mask for other applications (e.g. aviators) may not be suitablefor use in treating sleep disordered breathing, a mask designed for usein treating sleep disordered breathing may be suitable for otherapplications.

For these reasons, patient interfaces for delivery of CPAP during sleepform a distinct field.

2.2.3.1.1 Seal-Forming Portion

Patient interfaces may include a seal-forming portion. Since it is indirect contact with the patient's face, the shape and configuration ofthe seal-forming portion can have a direct impact the effectiveness andcomfort of the patient interface.

A patient interface may be partly characterised according to the designintent of where the seal-forming portion is to engage with the face inuse. In one form of patient interface, a seal-forming portion maycomprise two sub-portions to engage with respective left and rightnares. In one form of patient interface, a seal-forming portion maycomprise a single element that surrounds both nares in use. Such singleelement may be designed to for example overlay an upper lip region and anasal bridge region of a face. In one form of patient interface aseal-forming portion may comprise an element that surrounds a mouthregion in use, e.g. by forming a seal on a lower lip region of a face.In one form of patient interface, a seal-forming portion may comprise asingle element that surrounds both nares and a mouth region in use.These different types of patient interfaces may be known by a variety ofnames by their manufacturer including nasal masks, full-face masks,nasal pillows, nasal puffs and oro-nasal masks.

A seal-forming portion that may be effective in one region of apatient's face may be inappropriate in another region, e.g. because ofthe different shape, structure, variability and sensitivity regions ofthe patient's face. For example, a seal on swimming goggles thatoverlays a patient's forehead may not be appropriate to use on apatient's nose.

Certain seal-forming portions may be designed for mass manufacture suchthat one design fit and be comfortable and effective for a wide range ofdifferent face shapes and sizes. To the extent to which there is amismatch between the shape of the patient's face, and the seal-formingportion of the mass-manufactured patient interface, one or both mustadapt in order for a seal to form.

One type of seal-forming portion extends around the periphery of thepatient interface, and is intended to seal against the patient's facewhen force is applied to the patient interface with the seal-formingportion in confronting engagement with the patient's face. Theseal-forming portion may include an air or fluid filled cushion, or amoulded or formed surface of a resilient seal element made of anelastomer such as a rubber. With this type of seal-forming portion, ifthe fit is not adequate, there will be gaps between the seal-formingportion and the face, and additional force will be required to force thepatient interface against the face in order to achieve a seal.

Another type of seal-forming portion incorporates a flap seal of thinmaterial positioned about the periphery of the mask so as to provide aself-sealing action against the face of the patient when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to achieve a seal, or the mask mayleak. Furthermore, if the shape of the seal-forming portion does notmatch that of the patient, it may crease or buckle in use, giving riseto leaks.

Another type of seal-forming portion may comprise a friction-fitelement, e.g. for insertion into a naris, however some patients findthese uncomfortable.

Another form of seal-forming portion may use adhesive to achieve a seal.Some patients may find it inconvenient to constantly apply and remove anadhesive to their face.

A range of patient interface seal-forming portion technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT™ nasal pillows mask, SWIFT™ II nasal pillows mask,SWIFT™ LT nasal pillows mask, SWIFT™ FX nasal pillows mask and MIRAGELIBERTY™ full-face mask. The following patent applications, assigned toResMed Limited, describe examples of nasal pillows masks: InternationalPatent Application WO2004/073,778 (describing amongst other thingsaspects of the ResMed Limited SWIFT™ nasal pillows), US PatentApplication 2009/0044808 (describing amongst other things aspects of theResMed Limited SWIFT™ LT nasal pillows); International PatentApplications WO 2005/063,328 and WO 2006/130,903 (describing amongstother things aspects of the ResMed Limited MIRAGE LIBERTY™ full-facemask); International Patent Application WO 2009/052,560 (describingamongst other things aspects of the ResMed Limited SWIFT™ FX nasalpillows).

2.2.3.1.2 Positioning and Stabilising

A seal-forming portion of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming portion, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US PatentApplication Publication No. US 2010/0000534. However, the use ofadhesives may be uncomfortable for some.

Another technique is the use of one or more straps and/or stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

2.2.3.2 Respiratory Pressure Therapy (RPT) Device

Air pressure generators are known in a range of applications, e.g.industrial-scale ventilation systems. However, air pressure generatorsfor medical applications have particular requirements not fulfilled bymore generalised air pressure generators, such as the reliability, sizeand weight requirements of medical devices. In addition, even devicesdesigned for medical treatment may suffer from shortcomings, pertainingto one or more of: comfort, noise, ease of use, efficacy, size, weight,manufacturability, cost, and reliability.

An example of the special requirements of certain RPT devices isacoustic noise.

Table of noise output levels of prior RPT devices (one specimen only,measured using test method specified in ISO 3744 in CPAP mode at 10cmH₂O).

A-weighted sound Year RPT Device name pressure level dB (A) (approx.)C-Series Tango ™ 31.9 2007 C-Series Tango ™ with Humidifier 33.1 2007 S8Escape ™ II 30.5 2005 S8 Escape ™ II with H4i ™ 31.1 2005 Humidifier S9AutoSet ™ 26.5 2010 S9 AutoSet ™ with H5i Humidifier 28.6 2010

One known RPT device used for treating sleep disordered breathing is theS9 Sleep Therapy System, manufactured by ResMed Limited. Another exampleof an RPT device is a ventilator. Ventilators such as the ResMedStellar™ Series of Adult and Paediatric Ventilators may provide supportfor invasive and non-invasive non-dependent ventilation for a range ofpatients for treating a number of conditions such as but not limited toNMD, OHS and COPD.

The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator mayprovide support for invasive and non-invasive dependent ventilationsuitable for adult or pediatric patients for treating a number ofconditions. These ventilators provide volumetric and barometricventilation modes with a single or double limb circuit. RPT devicestypically comprise a pressure generator, such as a motor-driven bloweror a compressed gas reservoir, and are configured to supply a flow ofair to the airway of a patient. In some cases, the flow of air may besupplied to the airway of the patient at positive pressure. The outletof the RPT device is connected via an air circuit to a patient interfacesuch as those described above.

The designer of a device may be presented with an infinite number ofchoices to make. Design criteria often conflict, meaning that certaindesign choices are far from routine or inevitable. Furthermore, thecomfort and efficacy of certain aspects may be highly sensitive tosmall, subtle changes in one or more parameters.

2.2.3.3 Humidifier

Delivery of a flow of air without humidification may cause drying ofairways. The use of a humidifier with an RPT device and the patientinterface produces humidified gas that minimizes drying of the nasalmucosa and increases patient airway comfort. In addition in coolerclimates, warm air applied generally to the face area in and about thepatient interface is more comfortable than cold air. A range ofartificial humidification devices and systems are known, however theymay not fulfil the specialised requirements of a medical humidifier.

Medical humidifiers are used to increase humidity and/or temperature ofthe flow of air in relation to ambient air when required, typicallywhere the patient may be asleep or resting (e.g. at a hospital). Amedical humidifier for bedside placement may be small. A medicalhumidifier may be configured to only humidify and/or heat the flow ofair delivered to the patient without humidifying and/or heating thepatient's surroundings. Room-based systems (e.g. a sauna, an airconditioner, or an evaporative cooler), for example, may also humidifyair that is breathed in by the patient, however those systems would alsohumidify and/or heat the entire room, which may cause discomfort to theoccupants. Furthermore medical humidifiers may have more stringentsafety constraints than industrial humidifiers

While a number of medical humidifiers are known, they can suffer fromone or more shortcomings. Some medical humidifiers may provideinadequate humidification, some are difficult or inconvenient to use bypatients.

2.2.3.4 Data Management

There may be clinical reasons to obtain data to determine whether thepatient prescribed with respiratory therapy has been “compliant”, e.g.that the patient has used their RPT device according to certain a“compliance rule”. One example of a compliance rule for CPAP therapy isthat a patient, in order to be deemed compliant, is required to use theRPT device for at least four hours a night for at least 21 of 30consecutive days. In order to determine a patient's compliance, aprovider of the RPT device, such as a health care provider, may manuallyobtain data describing the patient's therapy using the RPT device,calculate the usage over a predetermined time period, and compare withthe compliance rule. Once the health care provider has determined thatthe patient has used their RPT device according to the compliance rule,the health care provider may notify a third party that the patient iscompliant.

There may be other aspects of a patient's therapy that would benefitfrom communication of therapy data to a third party or external system.

Existing processes to communicate and manage such data can be one ormore of costly, time-consuming, and error-prone.

2.2.3.5 Mandibular Repositioning

A mandibular repositioning device (MRD) or mandibular advancement device(MAD) is one of the treatment options for sleep apnea and snoring. It isan adjustable oral appliance available from a dentist or other supplierthat holds the lower jaw (mandible) in a forward position during sleep.The MRD is a removable device that a patient inserts into their mouthprior to going to sleep and removes following sleep. Thus, the MRD isnot designed to be worn all of the time. The MRD may be custom made orproduced in a standard form and includes a bite impression portiondesigned to allow fitting to a patient's teeth. This mechanicalprotrusion of the lower jaw expands the space behind the tongue, putstension on the pharyngeal walls to reduce collapse of the airway anddiminishes palate vibration.

In certain examples a mandibular advancement device may comprise anupper splint that is intended to engage with or fit over teeth on theupper jaw or maxilla and a lower splint that is intended to engage withor fit over teeth on the upper jaw or mandible. The upper and lowersplints are connected together laterally via a pair of connecting rods.The pair of connecting rods are fixed symmetrically on the upper splintand on the lower splint.

In such a design the length of the connecting rods is selected such thatwhen the MRD is placed in a patient's mouth the mandible is held in anadvanced position. The length of the connecting rods may be adjusted tochange the level of protrusion of the mandible. A dentist may determinea level of protrusion for the mandible that will determine the length ofthe connecting rods.

Some MRDs are structured to push the mandible forward relative to themaxilla while other MADs, such as the ResMed Narval CC™ MRD are designedto retain the mandible in a forward position. This device also reducesor minimises dental and temporo-mandibular joint (TMJ) side effects.Thus, it is configured to minimises or prevent any movement of one ormore of the teeth.

2.2.3.6 Vent Technologies

Some forms of treatment systems may include a vent to allow the washoutof exhaled carbon dioxide. The vent may allow a flow of gas from aninterior space of a patient interface, e.g., the plenum chamber, to anexterior of the patient interface, e.g., to ambient. The vent maycomprise an orifice and gas may flow through the orifice in use of themask. Many such vents are noisy. Others may become blocked in use andthus provide insufficient washout. Some vents may be disruptive of thesleep of a bed partner 1100 of the patient 1000, e.g. through noise orfocussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See International Patent Application Publication No. WO1998/034,665; International Patent Application Publication No. WO2000/078,381; U.S. Pat. No. 6,581,594; US Patent Application PublicationNo. US 2009/0050156; US Patent Application Publication No. 2009/0044808.

Table of noise of prior masks (ISO 17510-2:2007, 10 cmH₂O pressure at 1m)

A-weighted A-weighted sound sound power pressure level dB (A) dB (A)Year Mask name Mask type (uncertainty) (uncertainty) (approx.) Glue-on(*) nasal 50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard (*)ResMed nasal 29.5 21.5 1998 Mirage ™ (*) ResMed nasal 36 (3) 28 (3) 2000UltraMirage ™ ResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ™ ResMednasal 30 (3) 22 (3) 2008 Mirage Micro ™ ResMed nasal 29 (3) 22 (3) 2008Mirage ™ SoftGel ResMed nasal 26 (3) 18 (3) 2010 Mirage ™ FX ResMednasal pillows 37 29 2004 Mirage Swift ™ (*) ResMed nasal pillows 28 (3)20 (3) 2005 Mirage Swift ™ II ResMed nasal pillows 25 (3) 17 (3) 2008Mirage Swift ™ LT ResMed AirFit nasal pillows 21 (3) 13 (3) 2014 P10 (*)one specimen only, measured using test method specified in ISO 3744 inCPAP mode at 10 cmH₂O)Sound pressure values of a variety of objects arelisted below

A-weighted sound Object pressure dB (A) Notes Vacuum cleaner: Nilfisk 68ISO 3744 at 1 m Walter Broadly Litter Hog: B+ distance GradeConversational speech 60 1 m distance Average home 50 Quiet library 40Quiet bedroom at night 30 Background in TV studio 20

2.2.4 Diagnosis and Monitoring Systems

Polysomnography (PSG) is a conventional system for diagnosis andmonitoring of cardio-pulmonary disorders, and typically involves expertclinical staff to apply the system. PSG typically involves the placementof 15 to 20 contact sensors on a person in order to record variousbodily signals such as electroencephalography (EEG), electrocardiography(ECG), electrooculograpy (EOG), electromyography (EMG), etc. PSG forsleep disordered breathing has involved two nights of observation of apatient in a clinic, one night of pure diagnosis and a second night oftitration of treatment parameters by a clinician. PSG is thereforeexpensive and inconvenient. In particular it is unsuitable for homesleep testing.

Clinical experts may be able to diagnose or monitor patients adequatelybased on visual observation of PSG signals. However, there arecircumstances where a clinical expert may not be available, or aclinical expert may not be affordable. Different clinical experts maydisagree on a patient's condition. In addition, a given clinical expertmay apply a different standard at different times.

3 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the diagnosis, amelioration, treatment, or prevention ofrespiratory disorders having one or more of improved comfort, cost,efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to methods used in thediagnosis, amelioration, treatment or prevention of a respiratorydisorder.

An aspect of certain forms of the present technology is to providemethods and/or apparatus that improve the compliance of patients withrespiratory therapy.

Another aspect of the present technology relates to an elbow assemblyfor a patient interface including a swivel component adapted to connectto a patient interface and an elbow component adapted to connect to anair circuit. The swivel component is coupled to the elbow component by aball and socket joint and a hinge joint which allows the elbow componentto pivot relative to the swivel component about a single axis.

Another aspect of the present technology relates to an elbow assemblyfor a patient interface including a swivel component adapted to connectto a patient interface and an elbow component adapted to connect to anair circuit. The swivel component is coupled to the elbow component by ahinge joint which allows the elbow component to pivot relative to theswivel component about a single axis.

In an example, the swivel component includes a pair of spring armsstructured and arranged to connect to the patient interface. In anexample, the hinge joint is structured and arranged to prevent the elbowcomponent from rotating into or contacting the spring arms. In anexample, the swivel component includes a plurality of vent holes for gaswashout. In an example, the swivel component includes an inner radialwall and an outer radial wall that define a radial channel leading tothe plurality of vent holes. In an example, tracks or guide walls areprovided within the channel to provide discrete flow paths to theplurality of vent holes. In an example, at least a portion of the innerradial wall includes an inwardly extending lip or chevron structured andarranged to redirect flow in a manner that reduces noise and/orminimizes flow directly onto sensitive parts of the patient's face. Inan example, the elbow component includes a ball portion engaged withinan opening of the swivel component to form the ball and socket joint. Inan example, the ball portion includes a pair of opposed recesses engagedwith respective pivot pins of the swivel component to form the hingejoint. In an example, each of recesses includes tapered sides leading toa generally circular opening. In an example, the elbow component housesa pair of anti-asphyxia valves. In an example, the elbow componenthouses a pair of anti-asphyxia valves. In an example, the elbowcomponent includes a first end and a second end connected by anultrasonic weld connection. In an example, a swivel connector isprovided to the elbow component and adapted to connect to the aircircuit. In an example, the swivel connector is connected to the elbowcomponent by a snap-fit connection. In an example, the swivel connectoris connected to the elbow component by an overmold connection. In anexample, the swivel component comprises a hard-to-hard connection withthe patient interface. In an example, the swivel component is structuredto form a dynamic diametric seal and a dynamic face seal with thepatient interface to provide a tortuous leak path.

An aspect of certain forms of the present technology is a medical devicethat is easy to use, e.g. by a person who does not have medicaltraining, by a person who has limited dexterity, vision or by a personwith limited experience in using this type of medical device.

An aspect of one form of the present technology is a patient interfacethat may be washed in a home of a patient, e.g., in soapy water, withoutrequiring specialised cleaning equipment.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

4 BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

4.1 Treatment Systems

FIG. 1A shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal pillows, receiving a supply ofair at positive pressure from an RPT device 4000. Air from the RPTdevice 4000 is humidified in a humidifier 5000, and passes along an aircircuit 4170 to the patient 1000. A bed partner 1100 is also shown.

FIG. 1B shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal mask, receiving a supply of airat positive pressure from an RPT device 4000. Air from the RPT device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1C shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a full-face mask, receiving a supply ofair at positive pressure from an RPT device 4000. Air from the RPTdevice is humidified in a humidifier 5000, and passes along an aircircuit 4170 to the patient 1000.

4.2 Respiratory System and Facial Anatomy

FIG. 2A shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2B shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

FIG. 2C is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermilion, lowervermilion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion. Also indicated are the directionssuperior, inferior, radially inward and radially outward.

FIG. 2D is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, alar crest point,otobasion superior and otobasion inferior. Also indicated are thedirections superior & inferior, and anterior & posterior.

FIG. 2E is a further side view of a head. The approximate locations ofthe Frankfort horizontal and nasolabial angle are indicated. The coronalplane is also indicated.

FIG. 2F shows a base view of a nose with several features identifiedincluding naso-labial sulcus, lip inferior, upper Vermilion, naris,subnasale, columella, pronasale, the major axis of a naris and thesagittal plane.

FIG. 2G shows a side view of the superficial features of a nose.

FIG. 2H shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue,frontal process of the maxilla and fibrofatty tissue.

FIG. 2I shows a medial dissection of a nose, approximately severalmillimeters from a sagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage.

FIG. 2J shows a front view of the bones of a skull including thefrontal, nasal and zygomatic bones. Nasal concha are indicated, as arethe maxilla, and mandible.

FIG. 2K shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter, sternocleidomastoidand trapezius.

FIG. 2L shows an anterolateral view of a nose.

4.3 Patient Interface

FIG. 3A shows a patient interface in the form of a nasal mask inaccordance with one form of the present technology.

FIG. 3B shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3C.

FIG. 3C shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3B.

FIG. 3D shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a value of zero.

FIG. 3E shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3F.

FIG. 3F shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3E.

FIG. 3G shows a cushion for a mask that includes two pillows. Anexterior surface of the cushion is indicated. An edge of the surface isindicated. Dome and saddle regions are indicated.

FIG. 3H shows a cushion for a mask. An exterior surface of the cushionis indicated. An edge of the surface is indicated. A path on the surfacebetween points A and B is indicated. A straight line distance between Aand B is indicated. Two saddle regions and a dome region are indicated.

FIG. 3I shows the surface of a structure, with a one dimensional hole inthe surface. Plane curve 301D forms the boundary of a one dimensionalhole.

FIG. 3J shows a cross-section through the structure of FIG. 3I. Surface302D that bounds a two dimensional hole in the structure of FIG. 3I isindicated.

FIG. 3K shows a perspective view of the structure of FIG. 3I, includingthe two dimensional hole and the one dimensional hole. Surface 302D thatbounds a two dimensional hole in the structure of FIG. 3I is indicated.

FIG. 3L shows a mask having an inflatable bladder as a cushion.

FIG. 3M shows a cross-section through the mask of FIG. 3L, and shows theinside surface of the bladder.

FIG. 3N illustrates a left-hand rule.

FIG. 3O illustrates a right-hand rule.

FIG. 3P shows a left ear, including a left ear helix.

FIG. 3Q shows a right ear, including a right ear helix.

FIG. 3R shows a right-hand helix.

FIG. 3S shows a view of a mask, including the sign of the torsion of thespace curve defined by the edge of the sealing membrane in differentregions of the mask.

FIG. 4 is a perspective view of a patient interface shown on a patient'shead including an elbow assembly according to an example of the presenttechnology.

FIG. 5 is a perspective view of the patient interface shown in FIG. 4with the headgear removed.

FIG. 6 is a front view of the patient interface shown in FIG. 5.

FIG. 7 is a side view of the patient interface shown in FIG. 5.

FIG. 8 is an exploded view of the patient interface of FIG. 5 showingthe cushion assembly and frame assembly removably connected with theelbow assembly removed.

FIG. 9 is a cross-sectional view of the patient interface shown in FIG.7.

FIG. 10 is a cross-sectional view of the patient interface shown in FIG.5.

FIG. 11 is an enlarged view of the patient interface shown in FIG. 10.

FIG. 12 is a front perspective view of an elbow assembly according to anexample of the present technology.

FIG. 13 is a rear perspective view of the elbow assembly shown in FIG.12.

FIG. 14 is a side view of the elbow assembly shown in FIG. 12.

FIG. 15 is a front view of the elbow assembly shown in FIG. 12.

FIG. 16 is a rear view of the elbow assembly shown in FIG. 12.

FIG. 17 is a top view of the elbow assembly shown in FIG. 12.

FIG. 18 is a bottom view of the elbow assembly shown in FIG. 12.

FIG. 19 is a front exploded view of the elbow assembly shown in FIG. 12.

FIG. 20 is a rear exploded view of the elbow assembly shown in FIG. 12.

FIG. 21 is a cross-sectional view of the elbow assembly shown in FIG.15.

FIG. 22 is a cross-sectional view of the elbow assembly shown in FIG.14.

FIG. 23 is a cross-sectional view of the elbow assembly shown in FIG.14.

FIG. 24 is a cross-sectional view of the elbow assembly shown in FIG.14.

FIG. 25 is a front perspective view of an elbow assembly according to anexample of the present technology.

FIG. 26 is a rear perspective view of the elbow assembly shown in FIG.25.

FIG. 27 is a side view of the elbow assembly shown in FIG. 25.

FIG. 28 is a front view of the elbow assembly shown in FIG. 25.

FIG. 29 is another front view of the elbow assembly shown in FIG. 25.

FIG. 30 is a rear view of the elbow assembly shown in FIG. 25.

FIG. 31 is a top view of the elbow assembly shown in FIG. 25.

FIG. 32 is a bottom view of the elbow assembly shown in FIG. 25.

FIG. 33 is a front exploded view of the elbow assembly shown in FIG. 25.

FIG. 34 is a rear exploded view of the elbow assembly shown in FIG. 25.

FIG. 35 is a cross-sectional view of the elbow assembly shown in FIG.28.

FIG. 36 is a perspective view of the cross-section of FIG. 35.

FIG. 37 is a cross-sectional view of the elbow assembly shown in FIG.27.

FIG. 38 is a cross-sectional view of the elbow assembly shown in FIG.27.

FIG. 39 is a cross-sectional view of the elbow assembly shown in FIG.30.

FIG. 40 is a cross-sectional view of the elbow assembly shown in FIG.27.

FIG. 41 is an enlarged portion of the cross-section of FIG. 40.

FIG. 42 is a perspective view of the cross-section of FIG. 40.

FIG. 43 is an enlarged portion of the cross-section of FIG. 42.

FIG. 44 is a perspective view of a swivel component of the elbowassembly shown in FIG. 25.

FIG. 45 is a perspective view of a first end of an elbow component ofthe elbow assembly shown in FIG. 25.

FIG. 46 is a perspective view of a second end of an elbow component ofthe elbow assembly shown in FIG. 25.

FIG. 47 is a cross-sectional view showing a cushion assembly and frameassembly removably connected with the elbow assembly shown in FIG. 25assembly according to an example of the present technology.

FIG. 48A is a perspective view of a patient interface shown on apatient's head including an elbow assembly according to an example ofthe present technology.

FIG. 48B is a perspective view of the patient interface shown in FIG.48A with the elbow component of the elbow assembly pivoted upwardsrelative to the elbow component of the elbow assembly shown in FIG. 48A.

FIG. 48C is a perspective view of the patient interface shown in FIG.48A with the elbow assembly rotated relative to the elbow assembly shownin FIG. 48A.

FIG. 48D is a perspective view of the patient interface shown in FIG.48C with the elbow component of the elbow assembly pivoted upwardsrelative to the elbow component of the elbow assembly shown in FIG. 48C.

FIG. 49 is a rear perspective view of an elbow assembly according to anexample of the present technology.

FIG. 50 is a rear view of the elbow assembly shown in FIG. 49.

FIG. 51 is a cross-sectional view of the elbow assembly shown in FIG.49.

FIG. 52 is a cross-sectional view of the elbow assembly shown in FIG.49, from a slight perspective angle.

FIG. 53 is a cross-sectional view of a patient interface shown on apatient's head including the elbow assembly of FIG. 49 according to anexample of the present technology.

5 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

The following description is provided in relation to various exampleswhich may share one or more common characteristics and/or features. Itis to be understood that one or more features of any one example may becombinable with one or more features of another example or otherexamples. In addition, any single feature or combination of features inany of the examples may constitute a further example.

5.1 Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising the step of applying positive pressureto the entrance of the airways of a patient 1000.

In certain examples of the present technology, a supply of air atpositive pressure is provided to the nasal passages of the patient viaone or both nares.

In certain examples of the present technology, mouth breathing islimited, restricted or prevented.

5.2 Treatment Systems

In one form, the present technology comprises an apparatus or device fortreating a respiratory disorder. The apparatus or device may comprise anRPT device 4000 for supplying pressurised air to the patient 1000 via anair circuit 4170 to a patient interface 3000, e.g. see FIGS. 1A to 1C.

5.3 Patient Interface

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure 3300, a vent 3400, one form of connection port3600 for connection to air circuit 4170, and a forehead support 3700. Insome forms a functional aspect may be provided by one or more physicalcomponents. In some forms, one physical component may provide one ormore functional aspects. In use the seal-forming structure 3100 isarranged to surround an entrance to the airways of the patient so as tofacilitate the supply of air at positive pressure to the airways.

FIGS. 4 to 11 show a non-invasive patient interface 6000 in accordancewith one aspect of the present technology comprising a frame assembly6100, a cushion assembly 6175 including a seal-forming structure 6200,an elbow assembly 6600, and a positioning and stabilising structure(e.g., headgear 6800). FIG. 4 is an exemplary view of the patientinterface 6000 on a patient's head, FIGS. 5 to 11 are exemplary views ofthe patient interface 6000 without headgear 6800, and FIGS. 12 to 24 areexemplary views of the elbow assembly 6600 according to an example ofthe present technology. In use, one form of the seal-forming structure6200 is arranged to surround an entrance to the airways of the patient1000 so as to facilitate the supply of air at positive pressure to theairways. The seal-forming structure 6200 (e.g., constructed of silicone)may also be commonly referred to as a cushion. In some forms, afunctional aspect may be provided by one or more physical components. Insome forms, one physical component may provide one or more functionalaspects.

In one form of the present technology, the frame assembly 6100 connectsas an intermediate component to the cushion assembly 6175 and the elbowassembly 6600. For example, the elbow assembly 6600 connects to theframe assembly 6100 (via a retention feature on the frame assembly)independently of the cushion assembly 6175 (e.g., see FIG. 8). However,the seal for the air flow path is formed between the elbow assembly 6600and the cushion assembly 6175, i.e., the frame assembly 6100 is not inthe air flow path (e.g., see FIGS. 9, 10, and 11).

In the example shown, the patient interface is a full-face/oro-nasalinterface type including a seal-forming structure 6200 structured toform a seal around the patient's nose and mouth. However, aspects of thepresent technology may be adapted for use with other suitable interfacetypes, e.g., nasal interface, nasal prongs.

Elbow Assembly

As shown in FIGS. 4 to 24, the elbow assembly 6600 includes a swivelcomponent 6610 that is repeatedly engageable with and removablydisengageable from the frame assembly 6100 of the patient interface 6000and an elbow component 6620 adapted to connect to the air circuit 4170,e.g., via a swivel connector 6625.

The swivel component 6610 is coupled to the elbow component 6620 by aball and socket joint and a hinge joint which allows the elbow component6620 to pivot relative to the swivel component 6610 about a single axis,i.e., the elbow component 6620 is prevented from rotating relative tothe swivel component 6610 in a plurality of axes by the hinge joint.

FIGS. 25 to 47 illustrate an elbow assembly 7600 according to anotherexample of the present technology. The elbow assembly 7600 includesswivel component 7610, elbow component 7620, and swivel connector 7625,with the swivel component 7610 coupled to the elbow component 7620 asdescribed above by a ball and socket joint and a hinge joint whichallows the elbow component 7620 to pivot relative to the swivelcomponent 7610 about a single axis.

FIGS. 48A to 53 show a patient interface 8000 and an elbow assembly 8600according to another example of the present technology. The elbowassembly 8600 is substantially similar to the elbow assembly 7600, i.e.,elbow assembly 8600 includes swivel component 8610 coupled to elbowcomponent 7620 by a ball and socket joint and a hinge joint. Incontrast, the swivel component 8610 of the elbow assembly 8600 comprisesstructure to redirect flow in a manner that reduces noise and/orminimizes flow directly onto sensitive parts of the patient's face asdescribed in greater detail below.

Vent Arrangement

In the illustrated example of FIGS. 4 to 24, the swivel component 6610includes a swivel member 6612, a diffuser material 6614, and a diffusercover 6616. The swivel member 6612 includes an inner wall 6630, an outerwall 6632, and a base wall 6634 between the inner and outer walls 6630,6632. A plurality of vent holes 6640 are provided along the base wall6634 (e.g., at least 30 vent holes, e.g., 30 to 60 vent holes) to permitthe exit of exhausted gases from the patient interface. As illustrated,the vent holes 6640 are arranged to define a substantially circularshape that rings around the opening 6635 defined by the inner wall 6630.In an example, each hole 6640 may include a contour or taper along itslength, e.g., each hole converges in the direction of exhausted gas.

The inner and outer walls 6630, 6632 define a channel (annulardepression) adapted to receive or house the diffuser material 6614 suchthat the diffuser material 6614 is positioned adjacent an outlet end ofthe each of the vent holes 6640. The diffuser cover 6616 is connected tothe swivel member 6612 to retain the diffuser material 6614 within thechannel. The diffuser cover 6616 includes a top wall and spaced apartside walls each including a retaining structure structured to secure thediffuser cover 6616 to the swivel member 6612 (e.g., diffuser coverpermanently attached to the swivel member). The spaced apart side wallsdefine openings or outlets 6618 therebetween that allow exhausted gasesto vent to atmosphere. Specifically, the swivel component 6610 providesa vent flow path that passes through the vent holes 6640, through thediffuser material 6614 within the channel, and exits to atmosphere viathe outlets 6618 of the diffuser cover 6616. Such arrangement allowsexhaust gas to be directed radially outwardly from the elbow assembly,i.e., diffuser cover 6616 redirects flow passing through the diffusermaterial 6614.

In an alternative example, the elbow assembly may be provided withoutdiffuser material. For example, as shown in the example of FIGS. 25 to47, the swivel component 7610 includes an inner radial wall 7630, anouter radial wall 7632, and a base wall 7634 between the inner and outerradial walls 7630, 7632. The inner and outer radial walls 7630, 7632define a radial channel 7633 leading to a plurality of vent holes 7640(e.g., at least 20 vent holes, e.g., 20 to 60 vent holes) provided alongthe outer radial wall 7632 to permit the exit of exhausted gases fromthe patient interface to atmosphere. As illustrated, the vent holes 7640are arranged along the outer radial wall 7632 to allow exhaust gas to bedirected radially outwardly from the elbow assembly 7600.

As best shown in FIGS. 30, 35, 36, 39, 42, and 43, tracks or guide walls7637 are provided within the channel 7633 proximate each vent hole 7640to provide discrete flow paths that direct exhaust gases to the ventholes 7640. In the illustrated example, each track or guide wall 7637extends radially between the inner and outer walls 7630, 7632 andcooperate to define flow paths or passageways 7639 leading to each venthole 7640, i.e., each vent hole 7640 includes an associated passageway7639 provided by the tracks or guide walls 7637.

In the illustrated embodiment, the vent holes 7640 and associatedpassageways 7639 are only provided along a portion of a perimeter of theelbow assembly, e.g., to accommodate pinch arms 7650 and/or avoid gaswashout being directed into the pinch arms 7650. As illustrated, theswivel component 7610 includes vent holes 7640 along an upper orsuperior portion of its perimeter and along sides of a lower or inferiorportion of its perimeter. However, it should be appreciated that ventholes may be provided along the entire perimeter of the swivel component7610 or one or more selected portions of its perimeter.

In the illustrated example, as best shown in FIGS. 40 to 43, each venthole 7640 and associated passageway 7639 includes a generally U-shapedcross-sectional shape, e.g., arched opening including generallyrectangular shape with one of the shorter walls having a contour.However, each vent hole 7640 and associated passageway 7639 may haveother suitable shapes to direct exhaust or washout gas.

In use, the inner radial wall 7630 projects posteriorly to function as abaffle and segregate the flow path of incoming pressurized air from theRPT device from the flow path of exhaust via the vent, e.g., to reducecyclic noise. Exhaust gas flows into the channel 7633 and then into thepassageways 7639 associated with respective vent holes 7640. As bestshown in FIGS. 35, 36, and 39, the base wall 7634 at the end of eachpassageway 7639 is curved so as to more smoothly guide exhaust flow froma generally axial direction as its travels down the passageway 7639 to agenerally radial direction as it exits the vent hole 7640 to atmosphere.

Similar to elbow assembly 7600 described above, the swivel component8610 of elbow assembly 8600 includes an inner radial wall 8630 and anouter radial wall 8632 that define a radial channel 8633 leading to aplurality of vent holes 8640 (e.g., at least 20 vent holes, e.g., 20 to60 vent holes) provided along the outer radial wall 8632 to permit theexit of exhausted gases from the patient interface to atmosphere (e.g.,as best shown in FIGS. 49 to 53).

However, in the example of FIGS. 49 to 53, at least a portion of theinner radial wall 8630 includes an inwardly extending lip or chevron8631 structured and arranged to redirect flow in a manner that reducesnoise and/or minimizes flow directly onto sensitive parts of thepatient's face.

In the illustrated example, the lip or chevron 8631 curves and extendsinwardly from the inner radial wall 8630 towards the flow path ofincoming pressurized air. As illustrated, the lip or chevron 8631 isprovided along an upper or superior portion of the perimeter of theinner wall 8630 (e.g., see FIGS. 49 and 50). However, it should beappreciated that the lip or chevron 8631 may be provided along theentire perimeter of the inner wall 8630 or one or more selected portionsof the inner wall's perimeter.

In use, as best shown in FIG. 53, the inner radial wall 7630 and the lipor chevron 8631 segregate the inlet flow of incoming pressurized airfrom the outlet flow of exhaust via the vent. Moreover, the lip orchevron 8631 is structured and arranged to redirect the inlet flow awayfrom the outlet flow such that wind shearing and turbulence associatednoise is reduced, e.g., vent noise is reduced by deflecting the airwhich generally hugs the top quadrant of the elbow assembly (avoidsair/wind shear). In an example, the lip or chevron 8631 is structuredand arranged to minimize frizzling, e.g., sizzling or sputtering noisefrom air flow.

In addition, as best shown in FIG. 53, the lip or chevron 8631 isstructured and arranged to redirect the inlet flow away from sensitiveparts of the patient's face such as the nose tip or pronasal, e.g.,which is known to cause a tickling sensation.

Pinch Arms

In the example of FIGS. 4 to 24, the swivel member 6612 includes a pairof resilient, quick release pinch arms 6650, i.e., cantilevered springarms or pinch buttons. Each of the spring or pinch arms 6650 includes abarbed end or tab 6652 structured to provide a mechanical interlock,e.g., snap-fit connection, with the frame assembly 6100.

In the example of FIGS. 25 to 47, the hinging portion 7655 of each pincharm 7650 includes a generally trapezoidal or tapered shape along itslength (e.g., see FIGS. 29, 40, and 44, i.e., the width of the hingingportion 7655 at its connection to the main body of the swivel component7610 is larger than the width of the hinging portion at its connectionto the pinch arm 7650. Such shape of the hinging portion 7655 allowsease of use, e.g., facilitates flexing of the pinch arm 7650 whilemaintaining sufficient bias for retention and allowing rotationalmovement on the frame assembly.

Also, the clearance or spacing C (e.g., see FIGS. 29 and 38) betweeneach pinch arm 7650 and the elbow component 7620 is tuned such that theelbow component 7620 acts as a stop to prevent each pinch arm 7650 frombeing pressed too far inwards towards the elbow component 7620, whichensures that each pinch arm 7650 returns to its original position forretaining the elbow assembly onto the frame assembly.

Each spring arm 7650 includes the barbed end or peg-catch 7652structured to provide the snap-fit connection with the frame assembly.Also, each spring arm 7650 includes a finger grip portion 7657, e.g.,square-shaped protrusion, adjacent a free end.

In the illustrated example, the swivel component 7610 may be comprisedof a material (e.g., Polybutylene terephthalate (PBT) such as Pocan)that is more flexible and resilient than a material of the elbowcomponent 7620 (e.g., polycarbonate such as Makrolon), which materialfacilitates flexing of the spring arms 7650 in use.

Similar to elbow assembly 7600 described above, in the example of FIGS.48A to 53, the swivel component 8610 of the elbow assembly 8600 includesa pair of resilient, quick release pinch arms 8650 structured to providea mechanical interlock, e.g., snap-fit connection, with the frameassembly 8100 of the patient interface 8000.

Inner and Outer Walls of Swivel Member

In the example of FIGS. 4 to 24, the inner wall 6630 of the swivelmember 6612 defines opening 6635 which provides the socket for the balland socket joint. In addition, a pair of opposed, protruding, andcylindrical pivot pins or pegs 6645 extend from the inner wall 6630 intothe opening 6635 for forming a hinge connection for the hinge joint.

Also, in the illustrated example of FIGS. 4 to 24, the outer wall 6632is structured to extend through the frame assembly 6100 and form a sealwith the cushion assembly 6175.

Similarly, the inner wall 7630 of swivel component 7610 defines opening7635 which provides the socket for the ball and socket joint. Also,cylindrical pivot pins or pegs 7645 extend from the inner wall 7630 forforming a hinge connection for the hinge joint. However, as describedbelow, in the example of FIGS. 25 to 47, the outer wall 7632 isstructured to engage and form a hard-to-hard connection and seal withthe frame assembly 7100 (see FIG. 47).

First and Second Ends of Elbow Component

In the illustrated example of FIGS. 4 to 24, the elbow component 6620includes a first end 6660 provided to the swivel member 6612 and asecond end 6670. The second end 6670 is provided with the swivelconnector 6625 (e.g., swivel connector permanently connected to thesecond end) adapted to connect to the air circuit 4170. In this example,the swivel connector 6625 is overmolded to the tubular end portion 6671of the second end 6670 (e.g., see FIG. 21). As illustrated, the tubularend portion 6671 defines a channel to receive and axially retain theswivel connector 6625 on the second end 6670.

The elbow component 7620 in FIGS. 25 to 47 includes a first end 7660provided to the swivel component 7610 and a second end 7670 providedwith the swivel connector 7625. In this example, the elbow component7620 and the swivel connector 7625 comprise separately molded componentsthat are subsequently mechanically connected to one another, e.g.,snap-fit connection. For example, the swivel connector 7625 may becomprised of a material (e.g., Polybutylene terephthalate (PBT) such asPocan) that is more flexible than a material of the elbow component 7620(e.g., polycarbonate such as Makrolon), thereby allowing the swivelconnector 7625 to flex over the tubular end portion 7671 of the secondend 7670 of the elbow component 7620. The tubular end portion 7671 ofthe second end 7670 includes a groove 7671A along its outer surfaceadapted to receive a tongue 7626 provided along an interior surface ofthe swivel connector 7625 (e.g., see FIG. 35), i.e., snap-fit tongue andgroove for swivelling connection. The connection between the elbowcomponent 7620 and the swivel connector 7625 also provides a tortuouspath therebetween to control and minimize leak.

Ball and Socket Joint and Hinge Joint

The first end 6660 of the elbow component 6620 includes a ball portion6662 which provides the ball for the ball and socket joint. In addition,the ball portion 6662 includes a pair of opposed recesses 6664 forforming a hinge connection for the hinge joint.

The ball portion 6662 is engaged within the opening 6635 of the swivelmember 6612 to form the ball and socket joint and the recesses 6664 areengaged with respective pivot pins 6645, e.g., with a snap-fit, to formthe hinge joint.

Similarly, the ball portion 7662 of the elbow component 7620 is engagedwithin the opening 7635 of the swivel component 7610 to form the balland socket joint, and the opposed recesses 7664 are engaged withrespective pivot pins 7645, e.g., with a snap-fit, to form the hingejoint. As illustrated, the opening 7635 includes a rim 7636 (e.g., seeFIGS. 35 and 44) which further retains the ball portion 7662 within theopening 7635.

In the example of FIGS. 25 to 47, each recess 7664 (also referred to asa peg engaging portion structured to engage with a respective pivot pinor peg 7645) includes tapered sides leading to a generally circularopening which configuration is structured to resiliently expand toengulf or more substantially enclose the pivot pin 7645 duringengagement. This type of engagement is structured to limit relativemovement between the ball portion 7662 and the opening 7635 of the balland socket joint, thereby providing a controlled clearance between theexterior surface provided by the ball portion 7662 and the interiorsurface provided by the opening 7635. The controlled clearance allowsany leak between the ball portion 7662 and the opening 7635 to berelatively the same in any relative configuration between the swivelcomponent 7610 and the elbow component 7620, thereby allowingpredictable leak which facilitates tuning of the vent arrangement.

AAV Assembly

The first and second ends 6660, 6670 (e.g., constructed of polycarbonatesuch as Makrolon) of the elbow component 6620 are coupled to one another(e.g., permanently connected) and structured to house a dual flap,anti-asphyxia valve (AAV) assembly including a pair of AAVs 6680 (e.g.,constructed of liquid silicone rubber (LSR)). The first end 6660includes a pair of ports 6665 that may be selectively closed byrespective flap portions 6682 of the AAVs 6680. If pressurized gasprovided to the elbow assembly is of sufficient magnitude, the flapportions 6682 of the AAVs 6680 will raise to block off the ports 6665.In this case, pressurized gas will be guided through the elbow assemblyfor delivery to the patient interface and the patient's airways. Ifpressurized gas is not of sufficient magnitude or not delivered, theflap portions 6682 will remain in the “rest” position (e.g., see FIGS.21 and 24) so that the patient can breathe in ambient air and exhalethrough the ports 6665.

The first end 6660 includes a pair of openings 6667, just belowrespective ports 6665, that are structured to secure the AAVs 6680within the elbow component. Each AAV 6680 includes a connecting portion6684 structured to lockingly engage within a corresponding opening 6667,e.g., mechanical interlock. Each flap portion 6682 is movably provided,e.g., hingedly connected by a hinge portion, to the connecting portion6684 which allows the flap portion 6682 to pivot to selectively closethe port 6665.

The second end 6670 includes a base wall 6672 that defines an interioropening selectively closed by respective flap portions 6682 of the AAVs6680. One or more ribs 6675 extend from the base wall 6672 into theopening to define stops for the flap portions 6682. In the illustratedexample, the base wall 6672 includes wall portions 6672A, 6672B (e.g.,see FIGS. 20 and 24) oriented at an angle with respect to one another,which orients the flap portions 6682 at an angle with respect to oneanother when in the “rest” position (e.g., see FIG. 24).

Similarly, the first and second ends 7660, 7670 (e.g., constructed ofpolycarbonate such as Makrolon) of the elbow component 7620 are coupledto one another and structured to house a pair of AAVs 7680. The firstend 7660 includes a pair of ports 7665 that may be selectively closed byrespective flap portions 7682 of the AAVs 7680 as described above. FIG.37 shows the flap portions 7682 in the “rest” position. Each AAV 7680includes a connecting portion 7684 structured to lockingly engage withina corresponding opening 7667 in the first end 7660, e.g., mechanicalinterlock.

As best shown in FIGS. 33, 34, and 46, the second end 7670 includes abase wall 7672 that defines a pair of openings or therapy ports 7673selectively closed by respective flap portions 7682 of the AAVs 7680.The openings 7673 are separated by a bridge 7674 which prevents the flapportions 7682 from contacting each other, thereby preventing frictionfrom interference between the flap portions 7682. Moreover, the bridge7674 prevents any gaps being formed between the flap portions 7682 toprevent exhausted gas escaping through the openings 7673 when the flapportions 7682 are in the “rest” position.

A rib 7675 extends from each side of the bridge 7674 into respectiveopenings 7673 to define stops for the flap portions 7682, e.g., preventflap portions 7682 from traveling below the bridge 7674 and sticking.

In the illustrated example, the base wall 7672 includes wall portions7672A, 7672B (e.g., see FIG. 46) oriented at an angle with respect toone another, which orients the flap portions 7682 at an angle withrespect to one another when in the “rest” position. Such arrangementpre-loads or pre-bends the flap portions 7682 such that the flapportions 7682 maintain a minimum force against the rim or edge (i.e.,sealing surfaces) of the openings 7673 to block the openings 7673 whenpressurized gas is not being delivered. The flap portions 7682 arestructured such that they completely block the openings 7673 in theinstance that therapy pressure ceases. This complete blockage preventsany exhaust gases from flowing through the openings 7673 and thensubsequently rebreathed by the patient (i.e., all exhausted gas exitsvia the AAV ports 7665). Also, the pre-loaded configuration maintainsthe flap portions 7682 in the rest or closed position during movement ofthe entire elbow assembly (i.e., resists opening during movement orunder gravity).

The hinge portion 7685 that pivotally or hingedly connects the flapportion 7682 to the connecting portion 7684 (e.g., see FIGS. 34 and 37)may be tuned to easily open under therapy pressure and completely blockthe AAV ports 7665.

FIGS. 49, 51 and 52 show an additional feature of the elbow connection,showing a rim 8665.1 that at least partially surrounds the port 8665.The rim surrounds three sides of the port in this example, and has atapering thickness along its two depending legs. The rim 8665.1 ispositioned and dimensioned to come into contact with a flap 8682 of acorresponding AAV if the elbow is pressurised. The rim minimizes surfacearea contact of the AAV with the inner wall of the elbow to minimise therisk of said AAV sticking to the inner wall. Sticking of the AAV to theinner wall of the elbow may cause the ports to remain blocked even whentherapy pressure ceases.

Connection of First and Second Ends of Elbow Component

In an example, the first and second ends of the elbow component 6620,7620 may be coupled to one another by ultrasonic welding to permanentlyconnect the first and second ends. In such arrangement, the first andsecond ends may include structure to facilitate orientation and weldingof the first and second ends.

In an example, as best shown in FIGS. 34 and 45, the first end 7660 ofelbow component 7620 includes elongated support grooves 7690 along itsouter perimeter which are adapted to be engaged with a welding nest thatpositions and supports the first end 7660 during the ultrasonic weldingprocess. Also, the first end 7660 of elbow component 7620 includesorientation features (e.g., opposing flat surfaces 7692 as shown in FIG.45) along its inner perimeter to locate and align the second end 7670.

As best shown in FIG. 46, the second end 7670 of elbow component 7620includes a welding bead 7695 structured to be ultrasonically welded tothe inner perimeter of the first end 7660. As illustrated, the weldingbead 7695 includes orientation features (e.g., opposing flat surfaces7696) corresponding to orientation features (e.g., opposing flatsurfaces 7692) of the first end 7660 to locate and align the weldingbead 7695 within the inner perimeter of the first end 7660. Also, thesecond end 7670 provides a flat surface 7698 opposite the bead 7695(e.g., see FIG. 35), which is adapted to be engaged with a welding hornthat applies acoustic vibration to the second end 7670 during theultrasonic welding process.

Assembly

In an example, assembly of the elbow assembly 7600 may compriseassembling the AAVs 7680 to the second end 7670 of the elbow component7620, connecting the first and second ends 7660, 7670 of the elbowcomponent 7620 (e.g., via ultrasonic welding), assembling the swivelconnector 7625 to the second end 7670 of the elbow component 7620 (e.g.,snap-fit connection), and then assembling the swivel component 7610 tothe elbow component 7620 (e.g., snap-fit connection). However, it shouldbe appreciated that assembly of the elbow assembly may comprisealternative steps and/or sequences.

Connection Between Elbow Assembly and Frame Assembly

The elbow assembly 6600 releasably connects to the frame assembly 6100via the pinch arms 6650, e.g., quick release snap-fit. The frameassembly 6100 includes a circular channel 6120 which is structured toreceive the barbed end 6652 of the pinch arms 6650 to releasably retainthe elbow assembly 6600 to the frame assembly 6100 and form a swivelconnection (e.g., see FIGS. 7 and 9), i.e., allow 360° free rotation ofthe elbow assembly 6600 relative to the frame assembly 6100 about theaxis of the circular channel (e.g., see arrow in FIG. 6).

As best shown in FIG. 47, the pinch arms 7650 of the elbow assembly 7600releasably connect to frame assembly 7100 in a similar manner, i.e.,barbed end 7652 of the pinch arms 7650 engage within circular channel7120 of frame assembly 7100, e.g., quick release snap-fit, to releasablyretain the elbow assembly 7600 to the frame assembly 7100 and form theswivel connection.

In the illustrated example, the swivel component 7610 of the elbowassembly 7600 and the corresponding bore in the frame assembly 7100communicating with the swivel component 7610 include a diameter (e.g.,about 25-35 mm) that is larger than a diameter (e.g., about 22 mm)provided by the swivel connector 7625 adapted to connect to the aircircuit or gas delivery tube.

Seal Between Elbow Assembly and Cushion Assembly

In the illustrated example of FIGS. 4 to 24, the cushion assembly 6175comprises a flexible flange or lip seal 6250 to provide a seal with theelbow assembly 6600. As shown in FIGS. 10 and 11, the elbow assembly6600 is structured to mechanically interlock with the frame assembly6100, but is structured and arranged to sealingly engage with sealingmembrane 6250 of the cushion assembly 6175 to form a seal for the airflow path, i.e., sealing mechanism is separate from the retentionfeatures.

As illustrated, the leading edge of the outer wall 6632 of the elbowassembly 6600 forms a face seal with the lip seal 6250. This form ofengagement minimises surface area contact to reduce friction, therebyallowing a seal to form between the components while allowing the elbowassembly 6600 to swivel freely relative to the frame and cushionassemblies 6100, 6175.

In an alternative arrangement, the elbow assembly 6600 may form asubstantially sealed engagement with the frame assembly 6100. Thesubstantially sealed engagement between the frame assembly 6100 and theelbow assembly 6600 may allow the elbow assembly 6600 to swivel freelywhile maintaining a controlled level of leak through said substantiallysealed engagement. In this arrangement, the frame assembly 6100 may forma separate sealed engagement with the cushion assembly 6175. Saidarrangement allows the cushion assembly 6175 to be disengaged from theframe assembly 6100 independently of the elbow assembly 6600, which maybe disengaged separately from the frame assembly 6100.

For example, as shown in FIG. 47, the elbow assembly 7600 is structuredto establish a hard-to-hard connection and seal with the frame assembly7100. As illustrated, a dynamic diametric seal is formed between thecylindrical outer surface 7632A of the outer wall 7632 of the elbowassembly 7600 and the inner surface 7115A of the annular flange 7115 ofthe frame assembly 7100. Also, the annular flange 7115 of the frameassembly 7100 comprises a radially inwardly extending ridge 7125 thatacts as a stop to prevent over-insertion of the elbow assembly 7600 intothe frame assembly 7100. The surface of the ridge 7125 also provides adynamic face seal with the leading edge or surface 7632B of the outerwall 7632 of the elbow assembly 7600. The diametric seal and the faceseal provided between surfaces 7632A, 7632B of the outer wall 7632 andsurfaces of the annular flange 7115/ridge 7125 provide two matingsurfaces of contact between the elbow assembly 7600 and the frameassembly 7100, which increases the surface area of contact between theelbow assembly 7600 and the frame assembly 7100. The two mating surfacesare configured and arranged to minimize and control leak by providing atortuous leak path, i.e., leak path between the two mating surfacesextends radially to axially from interior the patient interface toatmosphere.

Also, as shown in FIG. 47, the frame assembly 7100 is structured to forma static diametric seal and a static face seal with the cushion assembly7175 to minimize and control leak. As illustrated, the frame assembly7100 includes a channel 7105 adapted to receive a connecting portion7176 provided to the cushion assembly 7175. The leading edge 7176A ofthe connecting portion 7176 and the end wall 7105A of the channel 7105are configured and arranged to provide a static face seal, and the outerside 7176B of the connecting portion 7176 and the side wall 7105B of thechannel 7105 are configured and arranged to provide a static diametricseal.

Decoupling Arrangement

In the illustrated examples, the elbow assembly 6600, 7600, 8600provides two distinct forms of decoupling to allow free rotation of theelbow assembly 6600, 7600, 8600 relative to the frame assembly 6100,7100, 8100 and the cushion assembly 6175, 7175, 8175, e.g., to enhancethe decoupling of tube drag on the patient interface to prevent sealinstability.

The first form of decoupling is provided by the pinch arms 6650, 7650,8650 which form the swivel connection allowing 360° free rotation of theelbow assembly 6600, 7600, 8600 relative to the frame assembly 6100,7100, 8100 (e.g., see arrow in FIG. 6). Also, FIG. 48A shows an exampleof the elbow assembly 8600 in a first position and FIG. 48C shows anexample of the elbow assembly 8600 rotated to a second position relativeto the first position via the swivel connection.

The second form of decoupling is provided by the ball and socket jointand the hinge joint which allows the elbow component 6620, 7620, 8620 topivot relative to the swivel component 6610, 7610, 8610 about a singleaxis, e.g., about the axis of the pivot pins 6645, 7645 (e.g., see arrowin FIG. 7). Also, FIG. 48A shows an example of the elbow assembly 8600in a first position and FIG. 48B shows an example of the elbow assembly8600 pivoted upwards to a second position relative to the first positionvia the ball and socket joint and the hinge joint. FIG. 48D also showsthe elbow assembly rotated and pivoted upwards relative to the elbowassembly position shown in FIG. 48A. In an example, the ball and socketjoint and the hinge joint provide a range of movement of about 10-30degrees, e.g., range of movement of about 15 degrees, range of movementof about 25-30 degrees (e.g., 26 degrees). Such hinge connection betweenthe elbow component 6620, 7620, 8620 and the swivel component 6610,7610, 8610 prevents free swivelling or full 360 degree motion so as toprevent the elbow component 6620, 7620, 8620 from rotating into orcontacting the pinch arms 6650, 7650, 8650 (e.g., which mayinadvertently release the elbow assembly from the frame assembly). Thehinge connection between the elbow component 6620, 7620, 8620 and theswivel component 6610, 7610, 8610 also allows the pivot pins 6645, 7645to act as a stop for preventing complete insertion of the ball portion6662, 7652 into the opening or socket 6635, 7635.

Thus, the elbow assembly 6600, 7600, 8600 as a whole is allowed toswivel relative to the frame and cushion assemblies 6100, 6175, 7100,7175, 8100, 8175 while the elbow component 6620, 7620, 8620 is able topivot relative to the swivel component 6610, 7610, 8610 in any swivelposition of the elbow assembly 6600, 7600, 8600, i.e., the elbowcomponent 6620, 7620, 8620 is able to pivot relative to the swivelcomponent 6610, 7610, 8610 regardless of the orientation of therotational position of the elbow assembly 6600, 7600, 8600 relative tothe frame and cushion assemblies 6100, 6175, 7100, 7175, 8100, 8175.

5.3.1 Seal-Forming Structure

In one form of the present technology, a seal-forming structure providesa seal-forming surface, and may additionally provide a cushioningfunction.

A seal-forming structure in accordance with the present technology maybe constructed from a soft, flexible, resilient material such assilicone.

In one form, the seal-forming structure comprises a sealing flange and asupport flange. The sealing flange comprises a relatively thin memberwith a thickness of less than about 1 mm, for example about 0.25 mm toabout 0.45 mm, that extends around the perimeter of the plenum chamber.Support flange may be relatively thicker than the sealing flange. Thesupport flange is disposed between the sealing flange and the marginaledge of the plenum chamber, and extends at least part of the way aroundthe perimeter. The support flange is or includes a spring-like elementand functions to support the sealing flange from buckling in use. In usethe sealing flange can readily respond to system pressure in the plenumchamber acting on its underside to urge it into tight sealing engagementwith the face.

In one form the seal-forming portion of the non-invasive patientinterface comprises a pair of nasal puffs, or nasal pillows, each nasalpuff or nasal pillow being constructed and arranged to form a seal witha respective naris of the nose of a patient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose, a stalk, a flexible region on theunderside of the frusto-cone and connecting the frusto-cone to thestalk. In addition, the structure to which the nasal pillow of thepresent technology is connected includes a flexible region adjacent thebase of the stalk. The flexible regions can act in concert to facilitatea universal joint structure that is accommodating of relative movementboth displacement and angular of the frusto-cone and the structure towhich the nasal pillow is connected. For example, the frusto-cone may beaxially displaced towards the structure to which the stalk is connected.

In one form, the non-invasive patient interface comprises a seal-formingportion that forms a seal in use on an upper lip region (that is, thelip superior) of the patient's face.

In one form the non-invasive patient interface comprises a seal-formingportion that forms a seal in use on a chin-region of the patient's face.

In certain forms of the present technology, a seal-forming structure isconfigured to correspond to a particular size of head and/or shape offace. For example one form of a seal-forming structure is suitable for alarge sized head, but not a small sized head. In another example, a formof seal-forming structure is suitable for a small sized head, but not alarge sized head.

5.3.2 Plenum Chamber

The plenum chamber has a perimeter that is shaped to be complementary tothe surface contour of the face of an average person in the region wherea seal will form in use. In use, a marginal edge of the plenum chamberis positioned in close proximity to an adjacent surface of the face.Actual contact with the face is provided by the seal-forming structure.The seal-forming structure may extend in use about the entire perimeterof the plenum chamber.

5.3.3 Positioning and Stabilising Structure

The seal-forming structure of the patient interface of the presenttechnology may be held in sealing position in use by the positioning andstabilising structure.

In one form of the present technology, a positioning and stabilisingstructure is provided that is configured in a manner consistent withbeing worn by a patient while sleeping. In one example the positioningand stabilising structure 3300 has a low profile, or cross-sectionalthickness, to reduce the perceived or actual bulk of the apparatus. Inone example, the positioning and stabilising structure comprises atleast one strap having a rectangular cross-section. In one example thepositioning and stabilising structure comprises at least one flat strap.

In one form of the present technology, a positioning and stabilisingstructure comprises a strap constructed from a laminate of a fabricpatient-contacting layer, a foam inner layer and a fabric outer layer.In one form, the foam is porous to allow moisture, (e.g., sweat), topass through the strap. In one form, the fabric outer layer comprisesloop material to engage with a hook material portion.

In certain forms of the present technology, a positioning andstabilising structure comprises a strap that is extensible, e.g.resiliently extensible. For example the strap may be configured in useto be in tension, and to direct a force to draw a cushion into sealingcontact with a portion of a patient's face. In an example the strap maybe configured as a tie.

In certain forms of the present technology, a positioning andstabilising structure comprises a strap that is bendable and e.g.non-rigid. An advantage of this aspect is that the strap is morecomfortable for a patient to lie upon while the patient is sleeping.

In certain forms of the present technology, a positioning andstabilizing structure provides a retaining force configured tocorrespond to a particular size of head and/or shape of face. Forexample one form of positioning and stabilizing structure provides aretaining force suitable for a large sized head, but not a small sizedhead. In another example, a form of positioning and stabilizingstructure provides a retaining force suitable for a small sized head,but not a large sized head.

5.3.4 Vent

In one form, the patient interface includes a vent constructed andarranged to allow for the washout of exhaled gases, e.g. carbon dioxide.

One form of vent in accordance with the present technology comprises aplurality of holes, for example, about 20 to about 80 holes, or about 40to about 60 holes, or about 45 to about 55 holes.

The vent may be located in the plenum chamber. Alternatively, the ventis located in a decoupling structure, e.g., a swivel.

5.3.5 Decoupling Structure(s)

In one form the patient interface includes at least one decouplingstructure, for example, a swivel or a ball and socket.

5.3.6 Connection Port

Connection port allows for connection to the air circuit 4170.

5.3.7 Forehead Support

In the illustrated example, the frame assembly 6100 is provided withouta forehead support.

In another form, the patient interface may include a forehead support,e.g., the frame assembly may include a forehead support.

5.3.8 Anti-Asphyxia Valve

In one form, the patient interface includes an anti-asphyxia valve.

5.3.9 Ports

In one form of the present technology, a patient interface includes oneor more ports that allow access to the volume within the plenum chamber.In one form this allows a clinician to supply supplemental oxygen. Inone form, this allows for the direct measurement of a property of gaseswithin the plenum chamber, such as the pressure.

5.4 Glossary

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

5.4.1 General

Air: In certain forms of the present technology, air may be taken tomean atmospheric air, and in other forms of the present technology airmay be taken to mean some other combination of breathable gases, e.g.atmospheric air enriched with oxygen.

Ambient: In certain forms of the present technology, the term ambientwill be taken to mean (i) external of the treatment system or patient,and (ii) immediately surrounding the treatment system or patient.

For example, ambient humidity with respect to a humidifier may be thehumidity of air immediately surrounding the humidifier, e.g. thehumidity in the room where a patient is sleeping. Such ambient humiditymay be different to the humidity outside the room where a patient issleeping.

In another example, ambient pressure may be the pressure immediatelysurrounding or external to the body.

In certain forms, ambient (e.g., acoustic) noise may be considered to bethe background noise level in the room where a patient is located, otherthan for example, noise generated by an RPT device or emanating from amask or patient interface. Ambient noise may be generated by sourcesoutside the room.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in whichthe treatment pressure is automatically adjustable, e.g. from breath tobreath, between minimum and maximum limits, depending on the presence orabsence of indications of SDB events.

Continuous Positive Airway Pressure (CPAP) therapy: Respiratory pressuretherapy in which the treatment pressure is approximately constantthrough a respiratory cycle of a patient. In some forms, the pressure atthe entrance to the airways will be slightly higher during exhalation,and slightly lower during inhalation. In some forms, the pressure willvary between different respiratory cycles of the patient, for example,being increased in response to detection of indications of partial upperairway obstruction, and decreased in the absence of indications ofpartial upper airway obstruction.

Flow rate: The volume (or mass) of air delivered per unit time. Flowrate may refer to an instantaneous quantity. In some cases, a referenceto flow rate will be a reference to a scalar quantity, namely a quantityhaving magnitude only. In other cases, a reference to flow rate will bea reference to a vector quantity, namely a quantity having bothmagnitude and direction. Flow rate may be given the symbol Q. ‘Flowrate’ is sometimes shortened to simply ‘flow’.

In the example of patient respiration, a flow rate may be nominallypositive for the inspiratory portion of a breathing cycle of a patient,and hence negative for the expiratory portion of the breathing cycle ofa patient. Total flow rate, Qt, is the flow rate of air leaving the RPTdevice. Vent flow rate, Qv, is the flow rate of air leaving a vent toallow washout of exhaled gases. Leak flow rate, Ql, is the flow rate ofleak from a patient interface system or elsewhere. Respiratory flowrate, Qr, is the flow rate of air that is received into the patient'srespiratory system.

Leak: The word leak will be taken to be an unintended flow of air. Inone example, leak may occur as the result of an incomplete seal betweena mask and a patient's face. In another example leak may occur in aswivel elbow to the ambient.

Noise, conducted (acoustic): Conducted noise in the present documentrefers to noise which is carried to the patient by the pneumatic path,such as the air circuit and the patient interface as well as the airtherein. In one form, conducted noise may be quantified by measuringsound pressure levels at the end of an air circuit.

Noise, radiated (acoustic): Radiated noise in the present documentrefers to noise which is carried to the patient by the ambient air. Inone form, radiated noise may be quantified by measuring soundpower/pressure levels of the object in question according to ISO 3744.

Noise, vent (acoustic): Vent noise in the present document refers tonoise which is generated by the flow of air through any vents such asvent holes of the patient interface.

Patient: A person, whether or not they are suffering from a respiratorydisease.

Pressure: Force per unit area. Pressure may be expressed in a range ofunits, including cmH₂O, g-f/cm² and hectopascal. 1 cmH₂O is equal to 1g-f/cm² and is approximately 0.98 hectopascal. In this specification,unless otherwise stated, pressure is given in units of cmH₂O.

The pressure in the patient interface is given the symbol Pm, while thetreatment pressure, which represents a target value to be achieved bythe mask pressure Pm at the current instant of time, is given the symbolPt.

Respiratory Pressure Therapy (RPT): The application of a supply of airto an entrance to the airways at a treatment pressure that is typicallypositive with respect to atmosphere.

Ventilator: A mechanical device that provides pressure support to apatient to perform some or all of the work of breathing.

5.4.1.1 Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Corning.Another manufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, an exemplary form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using ASTMD2240.

Polycarbonate: a typically transparent thermoplastic polymer ofBisphenol-A Carbonate.

5.4.1.2 Mechanical Properties

Resilience: Ability of a material to absorb energy when deformedelastically and to release the energy upon unloading.

‘Resilient’: Will release substantially all of the energy when unloaded.Includes e.g. certain silicones, and thermoplastic elastomers.

Hardness: The ability of a material per se to resist deformation (e.g.described by a Young's Modulus, or an indentation hardness scalemeasured on a standardised sample size).

‘Soft’ materials may include silicone or thermo-plastic elastomer (TPE),and may, e.g. readily deform under finger pressure.

‘Hard’ materials may include polycarbonate, polypropylene, steel oraluminium, and may not e.g. readily deform under finger pressure.

Stiffness (or rigidity) of a structure or component: The ability of thestructure or component to resist deformation in response to an appliedload. The load may be a force or a moment, e.g. compression, tension,bending or torsion. The structure or component may offer differentresistances in different directions.

‘Floppy’ structure or component: A structure or component that willchange shape, e.g. bend, when caused to support its own weight, within arelatively short period of time such as 1 second.

‘Rigid’ structure or component: A structure or component that will notsubstantially change shape when subject to the loads typicallyencountered in use. An example of such a use may be setting up andmaintaining a patient interface in sealing relationship with an entranceto a patient's airways, e.g. at a load of approximately 20 to 30 cmH₂Opressure.

As an example, an I-beam may comprise a different bending stiffness(resistance to a bending load) in a first direction in comparison to asecond, orthogonal direction. In another example, a structure orcomponent may be floppy in a first direction and rigid in a seconddirection.

5.4.2 Respiratory Cycle

Apnea: According to some definitions, an apnea is said to have occurredwhen flow falls below a predetermined threshold for a duration, e.g. 10seconds. An obstructive apnea will be said to have occurred when,despite patient effort, some obstruction of the airway does not allowair to flow. A central apnea will be said to have occurred when an apneais detected that is due to a reduction in breathing effort, or theabsence of breathing effort, despite the airway being patent. A mixedapnea occurs when a reduction or absence of breathing effort coincideswith an obstructed airway.

Breathing rate: The rate of spontaneous respiration of a patient,usually measured in breaths per minute.

Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

Effort (breathing): The work done by a spontaneously breathing personattempting to breathe.

Expiratory portion of a breathing cycle: The period from the start ofexpiratory flow to the start of inspiratory flow.

Flow limitation: Flow limitation will be taken to be the state ofaffairs in a patient's respiration where an increase in effort by thepatient does not give rise to a corresponding increase in flow. Whereflow limitation occurs during an inspiratory portion of the breathingcycle it may be described as inspiratory flow limitation. Where flowlimitation occurs during an expiratory portion of the breathing cycle itmay be described as expiratory flow limitation.

Types of flow limited inspiratory waveforms:

(i) Flattened: Having a rise followed by a relatively flat portion,followed by a fall.

(ii) M-shaped: Having two local peaks, one at the leading edge, and oneat the trailing edge, and a relatively flat portion between the twopeaks.

(iii) Chair-shaped: Having a single local peak, the peak being at theleading edge, followed by a relatively flat portion.

(iv) Reverse-chair shaped: Having a relatively flat portion followed bysingle local peak, the peak being at the trailing edge.

Hypopnea: According to some definitions, a hypopnea is taken to be areduction in flow, but not a cessation of flow. In one form, a hypopneamay be said to have occurred when there is a reduction in flow below athreshold rate for a duration. A central hypopnea will be said to haveoccurred when a hypopnea is detected that is due to a reduction inbreathing effort. In one form in adults, either of the following may beregarded as being hypopneas:

(i) a 30% reduction in patient breathing for at least 10 seconds plus anassociated 4% desaturation; or(ii) a reduction in patient breathing (but less than 50%) for at least10 seconds, with an associated desaturation of at least 3% or anarousal.

Hyperpnea: An increase in flow to a level higher than normal.

Inspiratory portion of a breathing cycle: The period from the start ofinspiratory flow to the start of expiratory flow will be taken to be theinspiratory portion of a breathing cycle.

Patency (airway): The degree of the airway being open, or the extent towhich the airway is open. A patent airway is open. Airway patency may bequantified, for example with a value of one (1) being patent, and avalue of zero (0), being closed (obstructed).

Positive End-Expiratory Pressure (PEEP): The pressure above atmospherein the lungs that exists at the end of expiration.

Peak flow rate (Qpeak): The maximum value of flow rate during theinspiratory portion of the respiratory flow waveform.

Respiratory flow rate, patient airflow rate, respiratory airflow rate(Qr): These terms may be understood to refer to the RPT device'sestimate of respiratory airflow rate, as opposed to “true respiratoryflow rate” or “true respiratory airflow rate”, which is the actualrespiratory flow rate experienced by the patient, usually expressed inlitres per minute.

Tidal volume (Vt): The volume of air inhaled or exhaled during normalbreathing, when extra effort is not applied.

(inhalation) Time (Ti): The duration of the inspiratory portion of therespiratory flow rate waveform.

(exhalation) Time (Te): The duration of the expiratory portion of therespiratory flow rate waveform.

(total) Time (Ttot): The total duration between the start of oneinspiratory portion of a respiratory flow rate waveform and the start ofthe following inspiratory portion of the respiratory flow rate waveform.

Typical recent ventilation: The value of ventilation around which recentvalues of ventilation Vent over some predetermined timescale tend tocluster, that is, a measure of the central tendency of the recent valuesof ventilation.

Upper airway obstruction (UAO): includes both partial and total upperairway obstruction. This may be associated with a state of flowlimitation, in which the flow rate increases only slightly or may evendecrease as the pressure difference across the upper airway increases(Starling resistor behaviour).

Ventilation (Vent): A measure of a rate of gas being exchanged by thepatient's respiratory system. Measures of ventilation may include one orboth of inspiratory and expiratory flow, per unit time. When expressedas a volume per minute, this quantity is often referred to as “minuteventilation”. Minute ventilation is sometimes given simply as a volume,understood to be the volume per minute.

5.4.3 Ventilation

Adaptive Servo-Ventilator (ASV): A servo-ventilator that has achangeable, rather than fixed target ventilation. The changeable targetventilation may be learned from some characteristic of the patient, forexample, a respiratory characteristic of the patient.

Backup rate: A parameter of a ventilator that establishes the minimumbreathing rate (typically in number of breaths per minute) that theventilator will deliver to the patient, if not triggered by spontaneousrespiratory effort.

Cycled: The termination of a ventilator's inspiratory phase. When aventilator delivers a breath to a spontaneously breathing patient, atthe end of the inspiratory portion of the breathing cycle, theventilator is said to be cycled to stop delivering the breath.

Expiratory positive airway pressure (EPAP): a base pressure, to which apressure varying within the breath is added to produce the desired maskpressure which the ventilator will attempt to achieve at a given time.

End expiratory pressure (EEP): Desired mask pressure which theventilator will attempt to achieve at the end of the expiratory portionof the breath. If the pressure waveform template Π(Φ) is zero-valued atthe end of expiration, i.e. Π(Φ)=0 when Φ=1, the EEP is equal to theEPAP.

Inspiratory positive airway pressure (IPAP): Maximum desired maskpressure which the ventilator will attempt to achieve during theinspiratory portion of the breath.

Pressure support: A number that is indicative of the increase inpressure during ventilator inspiration over that during ventilatorexpiration, and generally means the difference in pressure between themaximum value during inspiration and the base pressure (e.g.,PS=IPAP−EPAP). In some contexts pressure support means the differencewhich the ventilator aims to achieve, rather than what it actuallyachieves.

Servo-ventilator: A ventilator that measures patient ventilation, has atarget ventilation, and which adjusts the level of pressure support tobring the patient ventilation towards the target ventilation.

Spontaneous/Timed (S/T): A mode of a ventilator or other device thatattempts to detect the initiation of a breath of a spontaneouslybreathing patient. If however, the device is unable to detect a breathwithin a predetermined period of time, the device will automaticallyinitiate delivery of the breath.

Swing: Equivalent term to pressure support.

Triggered: When a ventilator delivers a breath of air to a spontaneouslybreathing patient, it is said to be triggered to do so at the initiationof the respiratory portion of the breathing cycle by the patient'sefforts.

Typical recent ventilation: The typical recent ventilation Vtyp is thevalue around which recent measures of ventilation over somepredetermined timescale tend to cluster. For example, a measure of thecentral tendency of the measures of ventilation over recent history maybe a suitable value of a typical recent ventilation.

5.4.4 Anatomy 5.4.4.1 Anatomy of the Face

Ala: the external outer wall or “wing” of each nostril (plural: alar)

Alare: The most lateral point on the nasal ala.

Alar curvature (or alar crest) point: The most posterior point in thecurved base line of each ala, found in the crease formed by the union ofthe ala with the cheek.

Auricle: The whole external visible part of the ear.

(nose) Bony framework: The bony framework of the nose comprises thenasal bones, the frontal process of the maxillae and the nasal part ofthe frontal bone.

(nose) Cartilaginous framework: The cartilaginous framework of the nosecomprises the septal, lateral, major and minor cartilages.

Columella: the strip of skin that separates the nares and which runsfrom the pronasale to the upper lip.

Columella angle: The angle between the line drawn through the midpointof the nostril aperture and a line drawn perpendicular to the Frankfurthorizontal while intersecting subnasale.

Frankfort horizontal plane: A line extending from the most inferiorpoint of the orbital margin to the left tragion. The tragion is thedeepest point in the notch superior to the tragus of the auricle.

Glabella: Located on the soft tissue, the most prominent point in themidsagittal plane of the forehead.

Lateral nasal cartilage: A generally triangular plate of cartilage. Itssuperior margin is attached to the nasal bone and frontal process of themaxilla, and its inferior margin is connected to the greater alarcartilage.

Lip, lower (labrale inferius):

Lip, upper (labrale superius):

Greater alar cartilage: A plate of cartilage lying below the lateralnasal cartilage. It is curved around the anterior part of the naris. Itsposterior end is connected to the frontal process of the maxilla by atough fibrous membrane containing three or four minor cartilages of theala.

Nares (Nostrils): Approximately ellipsoidal apertures forming theentrance to the nasal cavity. The singular form of nares is naris(nostril). The nares are separated by the nasal septum.

Naso-labial sulcus or Naso-labial fold: The skin fold or groove thatruns from each side of the nose to the corners of the mouth, separatingthe cheeks from the upper lip.

Naso-labial angle: The angle between the columella and the upper lip,while intersecting subnasale.

Otobasion inferior: The lowest point of attachment of the auricle to theskin of the face.

Otobasion superior: The highest point of attachment of the auricle tothe skin of the face.

Pronasale: the most protruded point or tip of the nose, which can beidentified in lateral view of the rest of the portion of the head.

Philtrum: the midline groove that runs from lower border of the nasalseptum to the top of the lip in the upper lip region.

Pogonion: Located on the soft tissue, the most anterior midpoint of thechin.

Ridge (nasal): The nasal ridge is the midline prominence of the nose,extending from the Sellion to the Pronasale.

Sagittal plane: A vertical plane that passes from anterior (front) toposterior (rear) dividing the body into right and left halves.

Sellion: Located on the soft tissue, the most concave point overlyingthe area of the frontonasal suture.

Septal cartilage (nasal): The nasal septal cartilage forms part of theseptum and divides the front part of the nasal cavity.

Subalare: The point at the lower margin of the alar base, where the alarbase joins with the skin of the superior (upper) lip.

Subnasal point: Located on the soft tissue, the point at which thecolumella merges with the upper lip in the midsagittal plane.

Supramentale: The point of greatest concavity in the midline of thelower lip between labrale inferius and soft tissue pogonion

5.4.4.2 Anatomy of the Skull

Frontal bone: The frontal bone includes a large vertical portion, thesquama frontalis, corresponding to the region known as the forehead.

Mandible: The mandible forms the lower jaw. The mental protuberance isthe bony protuberance of the jaw that forms the chin.

Maxilla: The maxilla forms the upper jaw and is located above themandible and below the orbits. The frontal process of the maxillaprojects upwards by the side of the nose, and forms part of its lateralboundary.

Nasal bones: The nasal bones are two small oblong bones, varying in sizeand form in different individuals; they are placed side by side at themiddle and upper part of the face, and form, by their junction, the“bridge” of the nose.

Nasion: The intersection of the frontal bone and the two nasal bones, adepressed area directly between the eyes and superior to the bridge ofthe nose.

Occipital bone: The occipital bone is situated at the back and lowerpart of the cranium. It includes an oval aperture, the foramen magnum,through which the cranial cavity communicates with the vertebral canal.The curved plate behind the foramen magnum is the squama occipitalis.

Orbit: The bony cavity in the skull to contain the eyeball.

Parietal bones: The parietal bones are the bones that, when joinedtogether, form the roof and sides of the cranium.

Temporal bones: The temporal bones are situated on the bases and sidesof the skull, and support that part of the face known as the temple.

Zygomatic bones: The face includes two zygomatic bones, located in theupper and lateral parts of the face and forming the prominence of thecheek.

5.4.4.3 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

5.4.5 Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: An elbow is an example of a structure that directs an axis offlow of air travelling therethrough to change direction through anangle. In one form, the angle may be approximately 90 degrees. Inanother form, the angle may be more, or less than 90 degrees. The elbowmay have an approximately circular cross-section. In another form theelbow may have an oval or a rectangular cross-section. In certain formsan elbow may be rotatable with respect to a mating component, e.g. about360 degrees. In certain forms an elbow may be removable from a matingcomponent, e.g. via a snap connection. In certain forms, an elbow may beassembled to a mating component via a one-time snap during manufacture,but not removable by a patient.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Functional dead space:

Headgear: Headgear will be taken to mean a form of positioning andstabilizing structure designed for use on a head. For example theheadgear may comprise a collection of one or more struts, ties andstiffeners configured to locate and retain a patient interface inposition on a patient's face for delivery of respiratory therapy. Someties are formed of a soft, flexible, elastic material such as alaminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a mask plenum chamber will be taken to mean a portion ofa patient interface having walls at least partially enclosing a volumeof space, the volume having air therein pressurised above atmosphericpressure in use. A shell may form part of the walls of a mask plenumchamber.

Seal: May be a noun form (“a seal”) which refers to a structure, or averb form (“to seal”) which refers to the effect. Two elements may beconstructed and/or arranged to ‘seal’ or to effect ‘sealing’therebetween without requiring a separate ‘seal’ element per se.

Shell: A shell will be taken to mean a curved, relatively thin structurehaving bending, tensile and compressive stiffness. For example, a curvedstructural wall of a mask may be a shell. In some forms, a shell may befaceted. In some forms a shell may be airtight. In some forms a shellmay not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel (noun): A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. There may be little orno leak flow of air from the swivel in use.

Tie (noun): A structure designed to resist tension.

Vent: (noun): A structure that allows a flow of air from an interior ofthe mask, or conduit, to ambient air for clinically effective washout ofexhaled gases. For example, a clinically effective washout may involve aflow rate of about 10 litres per minute to about 100 litres per minute,depending on the mask design and treatment pressure.

5.4.6 Shape of Structures

Products in accordance with the present technology may comprise one ormore three-dimensional mechanical structures, for example a mask cushionor an impeller. The three-dimensional structures may be bounded bytwo-dimensional surfaces. These surfaces may be distinguished using alabel to describe an associated surface orientation, location, function,or some other characteristic. For example a structure may comprise oneor more of an anterior surface, a posterior surface, an interior surfaceand an exterior surface. In another example, a cushion structure maycomprise a face-contacting (e.g. outer) surface, and a separatenon-face-contacting (e.g. underside or inner) surface. In anotherexample, a structure may comprise a first surface and a second surface.

To facilitate describing the shape of the three-dimensional structuresand the surfaces, we first consider a cross-section through a surface ofthe structure at a point, p. See FIG. 3B to FIG. 3F, which illustrateexamples of cross-sections at point p on a surface, and the resultingplane curves. FIGS. 3B to 3F also illustrate an outward normal vector atp. The outward normal vector at p points away from the surface. In someexamples we describe the surface from the point of view of an imaginarysmall person standing upright on the surface.

5.4.6.1 Curvature in One Dimension

The curvature of a plane curve at p may be described as having a sign(e.g. positive, negative) and a magnitude (e.g. 1/radius of a circlethat just touches the curve at p).

Positive curvature: If the curve at p turns towards the outward normal,the curvature at that point will be taken to be positive (if theimaginary small person leaves the point p they must walk uphill). SeeFIG. 3B (relatively large positive curvature compared to FIG. 3C) andFIG. 3C (relatively small positive curvature compared to FIG. 3B). Suchcurves are often referred to as concave.

Zero curvature: If the curve at p is a straight line, the curvature willbe taken to be zero (if the imaginary small person leaves the point p,they can walk on a level, neither up nor down). See FIG. 3D.

Negative curvature: If the curve at p turns away from the outwardnormal, the curvature in that direction at that point will be taken tobe negative (if the imaginary small person leaves the point p they mustwalk downhill). See FIG. 3E (relatively small negative curvaturecompared to FIG. 3F) and FIG. 3F (relatively large negative curvaturecompared to FIG. 3E). Such curves are often referred to as convex.

5.4.6.2 Curvature of Two Dimensional Surfaces

A description of the shape at a given point on a two-dimensional surfacein accordance with the present technology may include multiple normalcross-sections. The multiple cross-sections may cut the surface in aplane that includes the outward normal (a “normal plane”), and eachcross-section may be taken in a different direction. Each cross-sectionresults in a plane curve with a corresponding curvature. The differentcurvatures at that point may have the same sign, or a different sign.Each of the curvatures at that point has a magnitude, e.g. relativelysmall. The plane curves in FIGS. 3B to 3F could be examples of suchmultiple cross-sections at a particular point.

Principal curvatures and directions: The directions of the normal planeswhere the curvature of the curve takes its maximum and minimum valuesare called the principal directions. In the examples of FIG. 3B to FIG.3F, the maximum curvature occurs in FIG. 3B, and the minimum occurs inFIG. 3F, hence FIG. 3B and FIG. 3F are cross sections in the principaldirections. The principal curvatures at p are the curvatures in theprincipal directions.

Region of a surface: A connected set of points on a surface. The set ofpoints in a region may have similar characteristics, e.g. curvatures orsigns.

Saddle region: A region where at each point, the principal curvatureshave opposite signs, that is, one is positive, and the other is negative(depending on the direction to which the imaginary person turns, theymay walk uphill or downhill).

Dome region: A region where at each point the principal curvatures havethe same sign, e.g. both positive (a “concave dome”) or both negative (a“convex dome”).

Cylindrical region: A region where one principal curvature is zero (or,for example, zero within manufacturing tolerances) and the otherprincipal curvature is non-zero.

Planar region: A region of a surface where both of the principalcurvatures are zero (or, for example, zero within manufacturingtolerances).

Edge of a surface: A boundary or limit of a surface or region.

Path: In certain forms of the present technology, ‘path’ will be takento mean a path in the mathematical—topological sense, e.g. a continuousspace curve from f(0) to f(1) on a surface. In certain forms of thepresent technology, a ‘path’ may be described as a route or course,including e.g. a set of points on a surface. (The path for the imaginaryperson is where they walk on the surface, and is analogous to a gardenpath).

Path length: In certain forms of the present technology, ‘path length’will be taken to the distance along the surface from f(0) to f(1), thatis, the distance along the path on the surface. There may be more thanone path between two points on a surface and such paths may havedifferent path lengths. (The path length for the imaginary person wouldbe the distance they have to walk on the surface along the path).

Straight-line distance: The straight-line distance is the distancebetween two points on a surface, but without regard to the surface. Onplanar regions, there would be a path on the surface having the samepath length as the straight-line distance between two points on thesurface. On non-planar surfaces, there may be no paths having the samepath length as the straight-line distance between two points. (For theimaginary person, the straight-line distance would correspond to thedistance ‘as the crow flies’.)

5.4.6.3 Space Curves

Space curves: Unlike a plane curve, a space curve does not necessarilylie in any particular plane. A space curve may be considered to be aone-dimensional piece of three-dimensional space. An imaginary personwalking on a strand of the DNA helix walks along a space curve. Atypical human left ear comprises a left-hand helix, see FIG. 3P. Atypical human right ear comprises a right-hand helix, see FIG. 3Q. FIG.3R shows a right-hand helix. The edge of a structure, e.g. the edge of amembrane or impeller, may follow a space curve. In general, a spacecurve may be described by a curvature and a torsion at each point on thespace curve. Torsion is a measure of how the curve turns out of a plane.Torsion has a sign and a magnitude. The torsion at a point on a spacecurve may be characterised with reference to the tangent, normal andbinormal vectors at that point.

Tangent unit vector (or unit tangent vector): For each point on a curve,a vector at the point specifies a direction from that point, as well asa magnitude. A tangent unit vector is a unit vector pointing in the samedirection as the curve at that point. If an imaginary person were flyingalong the curve and fell off her vehicle at a particular point, thedirection of the tangent vector is the direction she would betravelling.

Unit normal vector: As the imaginary person moves along the curve, thistangent vector itself changes. The unit vector pointing in the samedirection that the tangent vector is changing is called the unitprincipal normal vector. It is perpendicular to the tangent vector.

Binormal unit vector: The binormal unit vector is perpendicular to boththe tangent vector and the principal normal vector. Its direction may bedetermined by a right-hand rule (see e.g. FIG. 3O), or alternatively bya left-hand rule (FIG. 3N).

Osculating plane: The plane containing the unit tangent vector and theunit principal normal vector. See FIGS. 3N and 3O.

Torsion of a space curve: The torsion at a point of a space curve is themagnitude of the rate of change of the binormal unit vector at thatpoint. It measures how much the curve deviates from the osculatingplane. A space curve which lies in a plane has zero torsion. A spacecurve which deviates a relatively small amount from the osculating planewill have a relatively small magnitude of torsion (e.g. a gently slopinghelical path). A space curve which deviates a relatively large amountfrom the osculating plane will have a relatively large magnitude oftorsion (e.g. a steeply sloping helical path). With reference to FIG.3R, since T2>T1, the magnitude of the torsion near the top coils of thehelix of FIG. 3R is greater than the magnitude of the torsion of thebottom coils of the helix of FIG. 3R

With reference to the right-hand rule of FIG. 3O, a space curve turningtowards the direction of the right-hand binormal may be considered ashaving a right-hand positive torsion (e.g. a right-hand helix as shownin FIG. 3R). A space curve turning away from the direction of theright-hand binormal may be considered as having a right-hand negativetorsion (e.g. a left-hand helix).

Equivalently, and with reference to a left-hand rule (see FIG. 3N), aspace curve turning towards the direction of the left-hand binormal maybe considered as having a left-hand positive torsion (e.g. a left-handhelix). Hence left-hand positive is equivalent to right-hand negative.See FIG. 3S.

5.4.6.4 Holes

A surface may have a one-dimensional hole, e.g. a hole bounded by aplane curve or by a space curve. Thin structures (e.g. a membrane) witha hole, may be described as having a one-dimensional hole. See forexample the one dimensional hole in the surface of structure shown inFIG. 3I, bounded by the plane curve 301D.

A structure may have a two-dimensional hole, e.g. a hole bounded by asurface. For example, an inflatable tyre has a two dimensional holebounded by the inside surface of the tyre. In another example, a bladderwith a cavity for air or gel could have a two-dimensional hole. See forexample the cushion of FIG. 3L and the example cross-section therethrough in FIG. 3M. In a yet another example, a conduit may comprise aone-dimension hole (e.g. at its entrance or at its exit), and atwo-dimension hole bounded by the inside surface of the conduit. Seealso the two dimensional hole through the structure shown in FIG. 3K,bounded by surface 302D.

5.5 Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in Patent Office patent files orrecords, but otherwise reserves all copyright rights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being used to construct acomponent, obvious alternative materials with similar properties may beused as a substitute. Furthermore, unless specified to the contrary, anyand all components herein described are understood to be capable ofbeing manufactured and, as such, may be manufactured together orseparately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated herein by referencein their entirety to disclose and describe the methods and/or materialswhich are the subject of those publications. The publications discussedherein are provided solely for their disclosure prior to the filing dateof the present application. Nothing herein is to be construed as anadmission that the present technology is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dates,which may need to be independently confirmed.

The terms “comprises” and “comprising” should be interpreted asreferring to elements, components, or steps in a non-exclusive manner,indicating that the referenced elements, components, or steps may bepresent, or utilized, or combined with other elements, components, orsteps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular examples, it is to be understood that these examples aremerely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative examples and that other arrangements may be devisedwithout departing from the spirit and scope of the technology.

For example, it should be appreciated that one or more features of anyone elbow assembly example (e.g., elbow assemblies 6600, 7600, 8600) maybe combinable with one or more features of another elbow assemblyexample (e.g., elbow assemblies 6600, 7600, 8600) or other examplesrelated thereto. For example, one or more aspects of the elbow assembly8600 (e.g., lip or chevron 8631) may be incorporated into the elbowassembly 6600, 7600.

Also, it should be appreciated that one or more aspects of the presenttechnology may be combinable with one or more aspects of: PCTApplication No. PCT/AU2016/050891, filed Sep. 23, 2016 and entitled“Patient Interface”, which claims the benefit of U.S. ProvisionalApplication No. 62/222,593, filed Sep. 23, 2015 and U.S. ProvisionalApplication No. 62/376,961, filed Aug. 19, 2016; U.S. ProvisionalApplication No. 62/377,217, filed Aug. 19, 2016 and entitled “PatientInterface with a Seal-Forming Structure having Varying Thickness”; U.S.Provisional Application No. 62/377,158, filed Aug. 19, 2016 and entitled“Patient Interface with a Seal-Forming Structure having VaryingThickness”; PCT Application No. PCT/AU2016/050893, filed Sep. 23, 2016and entitled “Vent Adaptor for a Respiratory Therapy System”, whichclaims the benefit of U.S. Provisional Application No. 62/222,604, filedSep. 23, 2015; and/or PCT Application No. PCT/AU2016/050228 filed Mar.24, 2016 and entitled “Patient Interface with Blowout Prevention forSeal-Forming Portion”, which claims the benefit of U.S. ProvisionalApplication No. 62/138,009, filed Mar. 25, 2015 and U.S. ProvisionalApplication No. 62/222,503, filed Sep. 23, 2015; each of the above-notedapplications of which is incorporated herein by reference in itsentirety.

5.6 Reference Signs List Number Feature Item

-   1000 patient-   1100 bed partner-   3000 patient interface-   3100 seal-forming structure-   3200 plenum chamber-   3300 positioning and stabilising structure-   3400 vent-   3600 connection port-   3700 forehead support-   4000 RPT device-   4170 air circuit-   5000 humidifier-   6000 patient interface-   6100 frame assembly-   6120 channel-   6175 cushion assembly-   6200 seal-forming structure-   6250 lip seal-   6600 elbow assembly-   6610 swivel component-   6612 swivel member-   6614 diffuser material-   6616 diffuser cover-   6618 outlet-   6620 elbow component-   6625 swivel connector-   6630 inner wall-   6632 outer wall-   6634 base wall-   6635 opening-   6640 vent hole-   6645 pivot pin-   6650 pinch arm-   6652 barbed end-   6660 first end-   6662 ball portion-   6664 recess-   6665 port-   6667 opening-   6670 second end-   6671 tubular end portion-   6672 base wall-   6672A wall portion-   6672B wall portion-   6675 rib-   6680 AAV-   6682 flap portion-   6684 connecting portion-   6800 headgear-   7100 frame assembly-   7105 channel-   7105A end wall-   7105B side wall-   7115 annular flange-   7115A inner surface-   7120 channel-   7125 ridge-   7175 cushion assembly-   7176 connecting portion-   7176A leading edge-   7176B outer side-   7600 elbow assembly-   7610 swivel component-   7620 elbow component-   7625 swivel connector-   7626 tongue-   7630 inner wall-   7632 outer wall-   7632A outer surface-   7632B leading edge-   7633 channel-   7634 base wall-   7635 opening-   7636 rim-   7637 track-   7639 passageway-   7640 vent hole-   7645 pivot pin-   7650 pinch arm-   7652 barbed end-   7655 hinging portion-   7657 finger grip-   7660 first end-   7662 ball portion-   7664 recess-   7665 port-   7667 opening-   7670 second end-   7671 tubular end portion-   7671A groove-   7672 base wall-   7672A wall portion-   7672B wall portion-   7673 opening-   7674 bridge-   7675 rib-   7680 AAV-   7682 flap portion-   7684 connecting portion-   7685 hinge portion-   7690 groove-   7692 flat surface-   7695 welding bead-   7696 flat surface-   7698 flat surface-   8000 patient interface-   8100 frame assembly-   8175 cushion assembly-   8600 elbow assembly-   8610 swivel component-   8620 elbow component-   8630 inner wall-   8631 lip or chevron-   8632 outer wall-   8633 channel-   8640 vent hole-   8650 pinch arm-   8665 port-   8665.1 rim-   8682 AAV flap

1. An elbow assembly for a patient interface, the elbow assemblycomprising: a swivel component adapted to connect to a patientinterface; and an elbow component adapted to connect to an air circuit,wherein the swivel component is coupled to the elbow component by a balland socket joint and a hinge joint which allows the elbow component topivot relative to the swivel component about a single pivot axis,wherein the swivel component and the elbow component, when coupled,provide a flow path therethrough from the air circuit to the patientinterface, and wherein the swivel component is adapted to allow rotationof the elbow assembly relative to the patient interface about a swivelaxis that extends transverse to said single pivot axis.
 2. The elbowassembly according to claim 1, wherein the swivel component includes apair of spring arms structured and arranged to connect to the patientinterface.
 3. The elbow assembly according to claim 2, wherein the hingejoint is structured and arranged to prevent the elbow component fromrotating into or contacting the spring arms.
 4. The elbow assemblyaccording to claim 1, wherein the swivel component includes a pluralityof vent holes for gas washout.
 5. The elbow assembly according to claim4, wherein the swivel component includes an inner radial wall and anouter radial wall that define a radial channel leading to the pluralityof vent holes.
 6. The elbow assembly according to claim 5, furthercomprising tracks or guide walls within the channel to provide discreteflow paths to the plurality of vent holes.
 7. The elbow assemblyaccording to claim 5, wherein at least a portion of the inner radialwall includes an inwardly extending lip or chevron structured andarranged to redirect flow in a manner that reduces noise and/orminimizes flow directly onto sensitive parts of a patient's face.
 8. Theelbow assembly according to claim 1, wherein the elbow componentincludes a ball portion engaged within an opening of the swivelcomponent to form the ball and socket joint.
 9. The elbow assemblyaccording to claim 8, wherein the ball portion includes a pair ofopposed recesses engaged with respective pivot pins of the swivelcomponent to form the hinge joint.
 10. The elbow assembly according toclaim 9, wherein each of recesses includes tapered sides leading to agenerally circular opening.
 11. The elbow assembly according to claim 1,wherein the elbow component houses a pair of anti-asphyxia valves. 12.The elbow assembly according to claim 1, wherein the elbow componentincludes a first end and a second end connected by an ultrasonic weldconnection.
 13. The elbow assembly according to claim 1, furthercomprising a swivel connector provided to the elbow component andadapted to connect to the air circuit.
 14. The elbow assembly accordingto claim 13, wherein the swivel connector is connected to the elbowcomponent by a snap-fit connection.
 15. The elbow assembly according toclaim 13, wherein the swivel connector is connected to the elbowcomponent by an overmold connection.
 16. The elbow assembly according toclaim 1, wherein the swivel component comprises a hard-to-hardconnection with the patient interface.
 17. The elbow assembly accordingto claim 1, wherein the swivel component is structured to form a dynamicdiametric seal and a dynamic face seal with the patient interface toprovide a tortuous leak path.
 18. The elbow assembly according to claim1, wherein the elbow component includes an anti-asphyxia valve,including a flap designed to close a port upon application ofpressurized gas, wherein the port is at least partly surrounded by a rimthat protrudes in order to engage the flap when pressure-biased to closethe port.
 19. The elbow assembly according to claim 1, wherein theswivel component is adapted to allow 360° free rotation of the elbowassembly relative to the patient interface about said swivel axis. 20.The elbow assembly according to claim 1, wherein the swivel componentcomprises a circular profile.